LIBRARY 

OF  THE 

UNIVERSITY  OF  CALIFORNIA. 

GIFT    OF 

?  PROF.  W.B.   RISING 

. 

Class 


f  & 


I 


CHEMICAL  PRIMER: 


AN   ELEMENTARY  WORK 


FOK  USE   IN 


SCHOOLS 


BY 


S.  P.  MEADS. 


OAKLAND,  CAL.  : 

PACIFIC  PRESS  PUBLISHING  HOUSE, 
TWELFTH  AND  CASTRO  STS. 


ENTERED  ACCORDING  TO  ACT  OF  CONGRESS  IN  THE  YEAR  188*2, 

BY  S.  P.  MEADS, 
JN  THE  OFFICE  OF  THE  LIBRARIAN  OF  CONGRESS,  AT  WASHINGTON,  D.  C 


I'ACIFIC  I'RRSS, 

PRINTERS,  bTKREOTYPKKg  AND  15INDBH&, 
OAKLAND,  CALIFORNIA. 


PREFACE. 


PHIS  Primer  has  been  prepared  for  use  in  those  High 
Schools  that  can  give  to  chemistry  only  one  term's  work. 
It  has  grown  out  of  the  needs  of  the  class-room,  as  I  have 
felt  them.  Its  statements  are  necessarily  somewhat  narrow, 
confining  the  pupil  to  general  rules.  Refined  accuracy  means 
a  treatise,  not  a  primer.  The  book  is  as  accurate  as  pains- 
taking can  make  a  work  of  its  aim  and  scope.  I  have  given 
in  its  pages  as  much  as  I  think  the  average  High  School  class 
can  digest  in  a  single  term,  and  I  hope  my  fellow-teachers  will 
carefully  examine  the  plan  throughout  before  passing  judgment. 
I  have  freely  consulted  whatever  chemical  works  were  within 
my  reach,  especially  Attfield,  Roscoe  and  Schorlemmer,  Eliot 
and  Storer,  Appleton,  and  Barker.  I  am  greatly  indebted  to 
Prof.  W.  B.  Rising  for  his  kindness  in  helping  me  down  from 
the  fence  upon  the  right  side  in  not  a  few  instances — indeed, 
I  might  say  over  the  fence,  in  some  cases.  My  thanks  are 
due  my  worthy  Principal,  Mr.  J.  B.  McChesney,  for  his 
uniform  encouragement.  I  am  under  lasting  obligation  to  my 
esteemed  co-laborer  in  the  High  School,  Mr.  C.  B.  Bradley,  for 
his  patient  assistance.  Many  ambiguous  and  obscure  state- 
ments, that  came  too  carelessly  from  my  pen,  have  been  made 
clear  and  intelligible  by  his  scholarly  criticism. 

Natural  Science  Dept.,  S.  P.  MEADS. 

Oakland  High  School,  May  1,  1882. 


237410 


Brief  Suggestions-Mixed. 


1T|O  not  allow  pupils  lazily  to  pronounce  the  symbol  or  the 
U  formula  instead  of  the  name;  i.  e. :  wherever  "H"  occurs, 

see  that  it  is  called  hydrogen Have  the  pupils  copy  the 

two  Reference  Tables  (pp.  16,  28)  upon  cardboard,  and  allow 
them  the  free  use  of  these  for  the  entire  term.  Never  compel 
them  to  memorize  formulas,  atomic  weights,  strength,  etc.  It 
is  as  important  to  know  what  not  to  remember,  as  to  know 
what  should  be  remembered,  since  the  former  comprises  by  far 

the  larger  portion  of  any  text- book Let  the  pupils  perform 

all  experiments  (except,  perhaps,  a  few  difficult  ones,  or  for  the 
sake  of  taking  your  turn  with  the  class)  in  presence  of  the 
class,  explaining  each  experiment  as  it  ^proceeds.  It  takes 
time,  but  it  is  the  only  way  to  teach  chemistry  where  a  table 
for  each  student  cannot  be  provided.  If  you  haven't  time, 
omit  half  the  experiments  to  accomplish  this  result.  Assign 
to  separate  pupils  one  experiment  each  a  few  days  beforehand. 
The  experiments  may  be  performed  upon  a  redwood  (plank) 

table  (see  FRONTISPIECE),  costing  not  over  three  dollars 

Every  experiment  teaches  something,  and  the  sooner  you  can 
impress  this  fact  the  better.  While  you  should  make  every 
experiment  as  impressive  as  it  can  be  made,  get  the  pupils 
through  the  babyhood  which  craves  noisy  or  showy  experi- 
ments, as  early  in  the  term  as  possible See  that  a  number 

of  larger  works  upon  chemistry  are  at  your  desk  for  reference. 

After  you  have  passed  the   "Reactions,"  encourage  any 

pupils  who  may  show  a  special  liking  for  the  science  to  work  out 
a  number  of  solutions  (not  too  complex,  and  mixed  by  you)  by 

the  Analytical  Charts Teach  pupils  to  use  small  flasks  and 

small  quantities  of  chemicals.  It  isn't  necessary  to  burn  a 
forest  to  prove  that  hydrocarbons  are  combustible,  nor  to  blow 

up  a  continent  to  prove  a   substance  explosive Don't   be 

afraid  to  teach  anything  contrary  to  the  text,  if  you  have  good 

authority  for  it  ;  but  let  disputed  points  alone Teach  any 

simple  principles  beyond  the  text,  instead  of  others  more  com- 
plex omitted;  but  don't  teach  intricate  matter  outside  of  text, 
else  the  result  will  be  pupils  will  know  neither  the  text  nor 

the  "intricate  matter." Use  the  metric  system  throughout; 

it  is  the  system.  Use  either  thermometer.  The  OKNTIORAPK 
is  used  in  this  book. 


INDEX 


PAGE. 

ACID  ACETIC 121 

"     Benzole 132 

"     Boracic 85 

'•     Carbolic 121,135 

"    Carbonic (H,  140 

"     Citric 124 

"     Gallic 124 

' '     Hydrochloric 73 

"     Lactic 141 

"  Malic..                              ..124 


Muriatic.  .  .  . 

Nitric 

Oleic 

Oxalic 

Palmitic .... 

Picric 

Prussic 

Salts 

Stearic 

Sulphuric.  .  . 
Tannic. . 


73 

58 

120 

123 

.....129 

127 

.  .50,  76 

76 

.129,  131 

.    ...  82 

..124 


"     Tartaric 124 

Acids 24,  134 

Aconite 126,  135 

Air 32,  40,  56,  65 

Albumen 122,  133,  138-9 

Alcohol 120,  121 

Alkalies 24,  134 

Alkaloids 124,  135 


Alloys 90,  112 

Aluminum 105,  128 

Amalgam 90 

Amber 182 

Ammonium 60,  1 1 1 

Ammonia 00 

"       Type 125 

Anaesthetic 57,  120,  121 

Analytical  Charts 142,  143 

Aniline 125-6-7 

Antidotes 132 

Antimony 90 

Antiseptic..  109,  110,  120,  121,  131 

Aqua-f ortis 58 

Aqua-regia 59 

Arsenicum 87,  133,  134 

Atomic  Theory 10  etc. 

Atmosphere 32,  46,  56,  65 

Atoms 10,  13 

BALSAMS 132 

Barium 1 07 

Bases , 24,   124 

Beer 120 

Basic  Salts 78 

Benzol 67,  122 

Bessemer's  Process 101 

Binary  Compounds 11,  17 

Bismuth..  ..103 


;  .  '  .  • 
0 

/  ,V  I)  K  X. 

Bleaching 

PAGK. 
I'l    81 

Combustion  
Copper  
Corrosive  Sublimate.  . 
Cotton 

J'AOE. 

32,  47 
99 
97 
117 

Blowpipe  
Borax 

51,68 

85 

Boroii.  . 

85 

Brass 

112 

Cream  of  Tartar 

1  23    1  24 

Bread-Making  
Brimstone  
Bromine 

122 
80 
74 

Creosote.  .  .  .  . 

.    121 

Cupellation. 

95 

Cyanogen  . 

76 

Bronze 

112 

DAVY'S  SAFETY  LAMP. 
Deliquescence.  .  . 

69 
54 
117 
118 
61 
1  19 

Bunsen's  Burner  

68 

CALCIUM  
-Light  
Calomel 

106 
138 
.  <)6 
132 
.  .  .07,  131 
132 
92 
118 

Dextrine  
Dextrose  
Diamond  
Diastase 

Camphor  
Candles  
Caoutchouc  
Carat  
Caramel 

Diffusion  of  Gases.  .  . 

51    56 

Disinfectant  
Distillation  

.02,  71,  121 
54 

127 

54 
16 

Carbon 

61 
.  .01,  140 
128 
.  .101,  102 
117 
106 

EFFLORESCENCE  
Elements  
Essences  

Carbonic  Oxide  
Carmine  
Cast-iron 

...121,  131 

59,  75 
120 
120 
120 

129 

Cellulose  
Chalk 

Etchings  
Ether  
Ethyl  Hydrate  
"     Oxide  

FATS  

Charcoal  

61 
67 

Chemistry  of  Candle.  .  . 
Chlorine  

Chloroform  
Chloral 

121 
121 
.  .    .  .       65 

Choke-damp.  . 

Fermentation  
Fireworks  
Flame  
Fluorine  

.  .  .119,  131 
.  .  .107,  109 
67 

75 

Chromium  
Cinnabar  
Clav 

1)0 

% 
inr: 

Coal  gas  .... 

67 

Formula,  Empirical   .  . 
"        Rational.  .  .  . 
Fusil  oil  

116 
116 
121 

Cobalt  

104 

1  ")R 

Coin 

112 

68 

Fusible  metal  

103 

<>7 
102 
67 

Coke.  .  .  . 

(lAJ.KNA  

Galvanized  Iron  
(Jas    Illuminating 

Collodion 

117 
121 

Compound  Ethers.  . 

"           Radical. 

IS 

INDEX. 


PAGB. 

Gelatin 122,  1'24 

German  Silver 11 

Glass 86 

Gluten 122 

Glue 122 

Glycerin   131 

Gold 1)1 

Graphite 61 

Gum 132 

Gun  Cotton 117 

Gunpowder 109 

Gutta-percha 132 

Gypsum 106 

HALOGENS 26,  70 

Hematite 100 

Hydrocarbons 4? 

Hydrogen 49 

Hydrogen  Sulphide .83 

INDIA-RUBBER 132 

Indigo 127 

Ink 71,  123,  124 

"  Printers' 71 

Iodine 74 

Iron 100 

Tsomerism 116 

LAUDANUM 126 

Laughing-gas 57 

Lead 97 

Leather 124 

Lime 106 

Lime-Light 138 

Linen 117 

Litmus 24 

Litharge 63 

Logwood 128 

Lunar  Caustic 95 

Lye 130 

MADDEK 128 

Magnesium 32 


PAGK. 

Malt 120 

Manganese 104 

Marble 106 

Marsh -gas .67 

Matches 84 

Mercury 96 

Metals 91 

Methyl  Alcohol 1*20 

Milk 118,  122 

Miscellaneous  Questions, 44,  79,  135 

Molasses 118 

Mordant 128 

Morphine 126,  135 

Mortar 106 

NAPTHA 108,  109 

Nascent  State 61 

Nickel 104 

Nicotine 126 

Nitre 109 

Nitrous  oxide 57 

Nitrogen 55 

Nomenclature 17,  23 

OILS 129 

Olein 129 

Opium 126 

Organic  Acids 123 

"       Bases 124 

"       Chemistry 116 

Oxides 33 

Oxygen 45 

Ozone 49 

PAPER 117 

Paregoric 126 

Pearlash 108 

Pencils 62 

Petrifaction 86 

Pewter 112 

Phosphorescence 85 

Phosphorus 84 


INDEX. 


PAGE. 

Photography 95 

Plants,  Office  of 65 

Plaster  of  Paris 106 

Platinum 93 

Plumbago 61 

Potash 108 

Potassium 108 

QUARTZ 86,  91 

Quicksilver 96 

Quinine 126 

REACTIONS 32 

Ref.  Table  1 16 

Ref.  Table  2 28 

Ref.  Table  2  (con) 141 

Resin 132 

RochelleSalt 77 

Rosin 132 

SAGO 117 

Sal-ammoniac 59 

Saleratus 108,  123 

Salt,  Common 1 10 

Salts 24 

Salts,  acid,  etc 76,  78 

Salts,  Epsom 105 

Salts,  Glauber's 110 

"      Rochelle 124 

Saltpetre 109 

Sand 86 

Selen-salts  78 

Shellac 107,  132 

Shot 112 

Silicon 86 

Silver 94 

Soap 129 

Sodium 10S 

Solder 112 

Solution.  .  .  36 


Spectrum  Analysis. .112 

Stalactites.. 106 

Starch 117 

Stearin 129 

Steel 101 

Strontium 107 

Strychnine 126,  135 

Sublimation 81 

Sugar,  Cane 118 

"      Grape 118,  139 

"      of  Lead 98 

Sulphur ; 80 

Sulph-Salts 78 


TAPIOCA 117 

Tar / 67 

Tartar  Emetic 90 

Tin 102 

Turpentine 131 

Type-metal 98 

VERDIGRIS 100 

Vermilion 96 

Ventilation 65,  66 

Vinegar 121,  134 

Vitriol,  Blue 100 

Green 102 

Oil  of 82 

WATKR 13,36,  52 

"      -type 24,  125 

White-lead 98 

Wines 120 

Woody  Fibre 117 


YEAST 

ZINC  . 


.123 
.102 


THEORETICAL  CHEMISTRY. 


CHAPTER  I. 


MATTER  exists  in  three  states: — 

1.  Solid:  Ex.,  iron,  lead,  ice. 

2.  Liquid:  Ex.,  mercury,  bromine,  water. 

3.  Gaseous:  Ex.,  hydrogen,  air,  steam. 

Nearly  all  substances  ordinarily  in  the  solid  state  may,  by  applying 
heat  (and  removing  pressure),  be  made  first  liquid  and  then  gaseous. 
Nearly  all  gases,  by  cold  and  pressure,  may  be  made  first  liquid  and  then 
solid. 

A  change  which  merely  converts  a  solid  to  a  liquid,  or  a  liquid  to  a 
gas,  or  vice  versa,  however  wonderful  such  change  may  be,  is  not  a 
chemical,  but  a  physical  change.  Ex.,  Ice  may  be  heated  and  con- 
verted into  water,  a  liquid,  and  then  into  steam,  a  gas. 

All  such  changes  are  studied  in  Physics,  not  in  Chemistry.  Chemistry 
deals  with  such  changes  only  incidentally. 

The  molecules  (small,  invisible  particles)  of  a  solid  move  with  diffi- 
culty upon  each  other.  The  molecules  of  a  liquid  move  readily  upon 
each  other,  so  that  the  liquid  assumes  the  shape  of  the  vessel  holding 
it.  The  molecules  of  gas  have  an  apparent  repulsion  for  each  other,  so 
that  a  gas,  regardless  of  its  specific  gravity  (i.  e.  whether  light  or 
heavy),  escapes  from  an  open  vessel  and  diffuses  itself  throughout  the 
surrounding  space. 


10  CHEMICAL  PRIMER. 


CHAPTER    II. 


The  Atomic  Theory  divides  matter  into:— 

1.  Mass. — Any  portion  of  matter  appreciable  by  the 

senses. 

2.  Molecule. — The   smallest   particle   of   matter  that 
can  take  part  in  a  mere  physical  change.     It  may  exist 
alone. 

3.  Atom. — The  smallest  particle  of  matter  that    can 
take  part  in  a  chemical  change.     An  atom  does  not  exist 
alone.     Atoms  compose  molecules;  i.  e.,  two  or  more  atoms 
make  a  molecule. 

Chemistry  treats  of  the  atomic  condition  of  matter 
and  especially  of  atomic  changes. 

It  will  be  inferred  from  the  definitions  that  a  mass  may  be  very  large 
or  exceedingly  small,  also,  that  the  molecule  and  the  atom  are  not 
visible  even  with  the  aid  of  the  most  powerful  microscope,  otherwise 
they  would  be  "appreciable  by  the  senses." 

Chemistry  treats  of  more  subtle  changes  than  physics.  If  the  mole- 
cule is  not  broken  up  and  the  atoms' set  free  to  form  new  combinations, 
it  matters  not  how  violent,  or  how  wonderful  the  change  may  be,  it  is 
purely  physical  and  in  no  sense  chemical. 

Of  course,  atoms  "exist  alone"  during  the  instant  of  chemical 
change.  One  atom  may  rarely  make  a  molecule.  At  this  stage  the 
pupil  should  fix  the  great  rules,  and  not  trouble  himself  with  exceptions. 


THEORETICAL  CHEMISTRY.  11 


CHAPTER  III. 


An  Element  is  a  substance  whose  molecules  contain 
atoms  of  one  kind  only ;  therefore  it  cannot  be  separated 
into  two  or  more  different  kinds  of  substances.  Ex.,  gold, 
lead,  hydrogen. 

A  binary  compound  is  a  substance  which  has  two  dif- 
ferent kinds  of  atoms  in  its  molecule,  and  therefore,  can 
be  separated  into  two  different  kinds  of  substances.  Ex., 
water,  common  salt. 


A  molecule  of  hydrogen  may  be  represented  thus  |  H  H  j  in 
which  each  H  represents  an  atom  and  the  boundary  line  simply  the 
fact  that  the  two  atoms  of  hydrogen  are  bound  together  by  chemical 
bonds  into  one  molecule. 


A  molecule  of  water  may  be  represented  thus  |  HOH  |  or  more 
briefly,  thus  |  H.2O  |  or  still  more  briefly  by  omitting  the  boundary 
line,  thus  H2O.  This  means  that  in  a  molecule  of  watpr  there  are  two 
atoms  of  hydrogen  and  one  atom  of  oxygen. 

Practically  it  means  that  two  parts  by  volume  of  hydrogen  unite  M'ith 
one  part  by  volume  of  oxygen  to  form  the  binary  compound  which  we 
call  water.  (Take  this  for  granted  now:  we'll  prove  it  by  and  by.  See 
WATER,  index).  Thus,  two  gases  unite  to  form  a  liquid.  But  this  is  a 
chemical  change,  because  the  atoms  of  the  molecules  of  hydrogen  and 
of  oxygen  are  disturbed,  their  molecules  being  broken  up  to  form  new 
molecules  of  a  different  substance,  water.  The  change  may  be  repre- 
sented thus: — 


|  HH  |    I  HH  |  -f  |  00  j  =  |  H,0  I     |  H20 

This  means  that  two  molecules  of  hydrogen  and  one  molecule  of 
oxygen  break  up  into  separate  atoms  and  then  instantaneously  re-unite 
into  two  molecules  of  water. 


12  CHEMICAL  PRIMER. 

The  atomic  reaction  (beginning  at  the  instant  when  the  molecules 
are  broken  up)  may  be  written  thus: — 

H,  +  O  H,O 

Two  atoms  |  One  atom  One  molecule 

of   hydrogen.  of    oxygen  of  water, 

Chemical  changes  are  called  Reactions.  For  all  practical  purposes 
the  atomic  reaction  is  correct.  As  it  is  not  nearly  so  difficult  as  the 
molecular  reaction  (first  above)  it  alone  will  be  used  in  this  book. 

There  are  about  sixty-seven  elements  known,  and  these 
may  be  considered  the  alphabet  of  chemistry.  From  these 
all  chemical  compounds  are  formed,  as  words  from  letters. 
A  binary  compound  might  be  compared  to  a  word  of  two 
letters. 


THEORETICAL  CHEMISTRY.  13 


CHAPTER  IV. 


Atoms  of  different  elements  differ  in  three  essential 
respects  :— 

1.  In  weight. 

2.  In  quality. 

3.  In  strength. 

The  First  Difference  needs  no  explanation.  When  we  say  that 
atoms  differ  in  weight,  we  mean  that  they  differ  in  weight.  (Atoms  of 
the  same  element  have  always  the  same  weight). 

The  Second  Difference  needs  explanation.  The  quality  of  meat 
may  be  determined  by  eating  it,  and  the  quality  is  said  to  be  good  or 
bad.  The  quality  of.  cloth  may  be  told  by  wearing  it,  and  the  quality 
of  cloth  is  also  said  to  be  good  or  bad,  as  the  case  may  be. 

The  quality  of  an  atom  is  determined  by  electricity,  and  the  atom 
is  said  to  be,  not  good  or  bad,  but  positive  or  negative. 

If  a  current  of  electricity  from  two  or  more  of  Bunsen's  quart  cups 
be  passed  through  the  binary  compound  water,  the  water  will  be 
decomposed  and  bubbles  of  gas  will  appear  at  each  pole.  If  the  gas 
from  the  positive  pole  be  collected  (see  Fig.  No.  1 )  and  tested,  it  will 
prove  to  be  oxygen.  If  the  gas  from  the  negative  pole  be  collected  and 
tested,  it  will  prove  to  be  hydrogen  and  will  have  twice  the  volume  of 
the  oxygen. 

NOTE. — The  water  should  be  acidulated  slightly  with  sulphuric  acid. 
The  hydrogen  will  always  have  a  little  more  than  twice  the  volume  of 
the  oxygen,  because  the  liberated  oxygen  is  more  soluble  in  (the 
remaining)  water  than  the  hydrogen.  The  pupil  may  learn  right  here, 
that  a  gas  can  be  dissolved  in  water  just  as  well  as  a  solid.  The  nature  of 
a  mere  solution  will  be  explained  hereafter. 


14  CHEMICAL  PRIMER. 


Fig.  1.     A  A — Platinum  Ends  (poles,  or  electrodes). 

The  law  of  electricity  being  that  "like  electricities  repel  each  other  and 
unlike  attract," — as  oxygen  goes  to  the  positive  pole,  it  is  negative  to. 
hydrogen,  and  as  hydrogen  goes  to  the  negative  pole,  it  is  positive  to 
oxygen. 

Thus,  by  means  of  a  battery  acting  upon  their  compounds,  the  ele- 
ments may  be  arranged  with  reference  to  their  "quality," — but  an 
atom  of  an  element  is  always  positive  or  negative,  not  absolutely,  but 
relatively. 

For  example,  if  we  arrange  in  line  sixty-seven  boys  from  north  to 
south,  the  first  boy  would  be  a  north  boy  to  any  other.  The  second 
boy  would  be  a  south  boy  compared  with  the  first,  but  a  north  boy 
compared  with  the  third.  The  tenth  boy  would  be  a  south  boy  com- 
pared with  the  fourth,  but  a  north  boy  compared  with  the  fifteenth. 
Any  boy  would  be  a  south  boy  to  all  boys  north  of  himself,  but  a 
north  boy  to  all  boys  south  of  himself. 

Thus,  the  elements  are  arranged  inline  according  to  their  ' 'quality," 
oxygen  standing  first,  being  most  negative.  (See  Reference  Table  No.  1). 
This  difference  in  "quality"  is  of  the  utmost  importance  in  chemistry. 

The  Third  Difference  may  be  explained  by  an  illustration. 

If  one  man  can  hold  a  100  Ib.  weight,  we  may  call  his  strength  one. 
Then,  if  another  man  can  hold  two  100  Ib.  weights,  his  strength  would 
be  two,  and  it  would  take  two  of  the  first  kind  of  men  to  match  one  of 
the  second  kind.  If  a  third  man  can  hold  three  100  Ib.  weights,  his 


THEORETICAL  CHEMISTRY  15 

strength  would  be  three,  and  it  would  take  three  of  the  first  kind  of 
men  to  match  one  of  the  third.  But  how  shall  we  match  the  second 
kind  of  men  and  the  third  kind?  Evidently,  three  of  the  second  kind 
would  match  two  of  the  third  kind.  If  a  fourth  man  can  hold  four 
100  Ib,  weights,  his  strength  will  be  four;  etc. 

The  strength  of  atoms  is  measured,  not  by  100  Ib.  weights,  but  by 
the  strength  of  hydrogen  atoms.  The  strength  of  the  hydrogen  atom 
is  taken  as  one.  The  strength  of  those  elements  whose  atoms  each 
require  one  atom  of  hydrogen  to  match  them  is  one; — of  those  elements 
whose  atoms  each  require  two  atoms  of  hydrogen  to  match  them,  the 
strength  is  two; — of  those  whose  atoms  require  three  atoms  of  hydro- 
gen, the  strength  is  three,  etc. 

These  elements  are  called  respectively  monads  (1), 
dyads  (2),  triads  (3),  tetrads  (4),  pentads  (5),  hexads  (6), 
and  heptads  (7).  This  strength  of  the  atoms  is  often 
expressed  adjectively  by  the  terms,  univalent  (1),  bivalent 
(2),  trivalent  (3),  quadrivalent  (4),  pentivalent  (5),  etc. 


CHAPTER  V. 


The  names  of  the  elements  are  abbreviated  in  chemical 
language.  O  is  the  symbol  for  oxygen,  S  for  sulphur,  Sb 
for  antimony  (Latin,  stibium),  etc.  The  dictionary  will 
give  the  Latin  name  from  which  a  number  of  the  symbols 
are  derived. 

The  following  Reference  Table  exhibits  the  symbols  of 
the  elements  and  the  three  essential  differences  of  their 
atoms : — 


REFERENCE  TABLE  No.  1, 


SYMBOL. 

QUALITY. 

Shown  by  order  of  iiaiues. 

ATOMIC 
WEIGHT. 

STRENGTH. 

Negative  End. 

0 

Oxygen 

16 

2 

s 

Sulphur 

32 

2 

N 

Nitrogen 

14 

3 

fF 

Fluorine 

19 

1 

|ci 

Chlorine 

35.5 

1 

Bromine 

80 

1 

1  / 

Iodine 

127 

1 

LCK 

Cyanogen* 

26 

1 

Se 

Selenium 

79 

2 

P 

Phosphorus 

31 

5 

As 

Arsenicum 

75 

3 

Cr 

Chromium 

52.5 

2 

B 

Boron 

11 

3 

rfi>    C 

Carbon 

12 

4 

1      Sb 

Antimony 

122 

3 

Si 

Silicon 

28 

4 

H 

HYDROGEN 

1 

1 

Au 

Gold 

196.6 

3 

Platinum 

197 

4 

*r  Hg 

Mercury 

200 

2 

(and  Hg2  a  dyad) 

i;   Ag 

Silver 

108 

1 

T    Cu 

Copper 

63.5 

2 

(and  Cu2  a  dyad) 

Bi 

Bismuth 

210 

3 

Sn 

Tin 

118            4 

Pb 

Lead 

207 

2 

Co 

Cobalt 

59 

2 

Ni 

Nickel 

59 

2 

Fe 

Iron 

56 

2 

(and  Fe2  a  hex  ad) 

Zn 

Zinc 

65 

2 

Mn 

Manganese 

55 

2 

Al 

Aluminum 

27.5 

(A12  a  hexad) 

Mg 

Magnesium 

.       24 

2 

Ca 

Calcium 

40 

2 

Sr 

Strontium 

87.5 

2 

Ba 

Barium 

137 

2 

f  Na 

Sodium 

23 

1 

1    K 

Potassium 

39 

1 

(H^ 

Ammonium* 

18 

1 

Positive  End. 

(See  Chap.  VI). 


THEORETICAL  CHEMIST R  Y. 


CHAPTER  VI. 


A  binary  compound  is  named  by  placing  the  positive 
element  first  and  changing  the  ending  of  the  negative  into 
ide. 

EXAMPLE. 

Formula.  Name. 

Na  Cl   =  =  sodium  chloride. 
K2  O     =  potassium  oxide. 

It  will  be  noticed  that  sodium  and  chlorine  are  both  monads  (see 
strength  in  Reference  Table  No.  1),  and  therefore  it  requires  one  atom 
of  each  to  match  the  other  in  the  molecule,  as  in  the  first  example.  In 
the  second  example,  potassium  is  a  monad  (see  TABLE),  but  oxygen  is  a 
dyad,  therefore  it  takes  two  atoms  of  potassium  to  match  one  of  oxygen 
in  the  molecule. 

Again,  in  putting  dyads  and  triads  together,  we  must  take  three 
dyads  to  match  two  triads  in  the  molecule,  a  strength  of  two  times 
three  equaling  a  strength  of  three  times  two. 

EXAMPLE. 

As,  S3  —  Arsenicum  sulphide. 
Again,  two  dyads  must  be  taken  to  match  one  tetrad. 

EXAMPLE. 

C  O2  —  Carbon  oxide. 
Five  dyads  must  be  taken  to  match  two  pentads. 

EXAMPLE. 

P.j  O,-,  —  phosphorus  oxide. 
P2  S5  —  phosphorus  sulphide. 

NOTE. — Just  as  we  sometimes  say  "the  father  of  Mary,"  instead  of 
"Mary's  father,"  the  older  chemists  say  "sulphide  of  phosphorus," 
instead  of  "phosphorus  sulphide. "  (They  also  expressed  the  same  by 
"sulphwretf  of  phosphorus, "  or  "sulphuretted  phosphorus. ") 


18 


CHEMICAL  PRIMER. 


Atoms  of  two  or  more  elements  bound  together  by 
chemical  bonds  so  closely,  as  to  act  as  one  atom  in  the 
formation  of  compounds,  form  a  Compound  Radical. 

Two  very  important  compound  radicals  are  inserted  in  the  Reference 
Table  and  linked  with  the  elements  with  which  they  are  closely  allied. 
Their  compounds  with  a  single  element  are  considered  and  named  as 
binaries,  though  they  contain  three  different  kinds  of  atoms. 

EXAMPLE. 

K  CN  =•  potassium  cyanide. 
(H4N)2S  =  ammonium  sulphide. 
H4  N  CN  —  ammonium  cyanide. 

NOTE. — The  pupil  should  write  the 
formulas  and  names  of  a  great  many 
binary  compounds,  putting  the  atoms 
together  according  to  the  strength  in 
the  Reference  Table.  Be  careful  that 
the  multiplications  make  the  positives 
match  in  strength  the  negatives,  as  in 
the  examples.  It  does  not  matter  if 
many  of  the  compounds  are  merely 
theoretical.  It  is,  however,  a  great  gain 
at  this  point,  to  have  as  many  binaries 
as  combine  according  to  the  strength  given  in 


Fig  2. 


the  Table,  shown  to  the  scholars.  For  instance,  a  substance  might  be 
shown  and  the  class  told  that  it  was  a  compound  of  sulphur  and  sodium. 
They  should  then  all  write  labels  for  the  bottle  containing  it,  giving 
formula  and  name,  as  in  Fig  2. 


CHAPTER  VII. 


Ic  and  Ous  Binaries. 

These  may  be  introduced  by  an  illustration.  In  one  of  our  eastern 
townships  lived  a  man,  who  was  afflicted  with  periodic  insanity.  When 
in  his  right  mind  (ordinarily),  he  had  the  strength  of  his  brother.  He 
could  be  called  a  monad.  In  one  of  his  insane  fits  he  carried  three  men 
upon  his  back  over  a  gate  five  boards  high.  He  became  a  very  decided 
triad,  you  see. 


THEORETICAL  CHEMISTRY.  19 

Now,  the  Reference  Table  No.  1  gives  the  "strength"  of  chlorine 
one',  i.  e.  as  a  monad, — but  sometimes  it  acts  with  a  strength  of  three. 
i.  e.,  as  a  triad  (sometimes  as  a  pentad,  or  even  as  a  heptad). 

Carbon  is  given  a  strength  of  four,  and  this  it  ordinarily  has, — but 
sometimes  it  acts  with  a  strength  of  only  two.  Thus,  it  forms  two 
binary  compounds  with  oxygen,  CO2  and  CO.  Evidently,  if  we  say 
carbon  oxide,  we  shall  not  know  which  is  meant,  because  the  name  may 
apply  to  either. 

As  a  rule,  an  atom  with  an  even  strength  never  has  an  odd  strength, 
also,  an  atom  with  an  odd  strength  never  has  an  even  strength.  The 
strength  increases  or  decreases  by  twos.  This  will  be  noticed  as  we 
proceed. 

We  must  invent  some  way  to  distinguish  the  different  compounds, 
when  an  element  acts  with  different  strengths. 

When  the  positive  takes  more  of  the  negative,  it  has  the 
ending  ic,  when  it  takes  less  of  the  negative,  it  has  the 
ending  OUS. 

EXAMPLE. 

C  O2  =  carbonic  oxide. 
C  O  =  carbonous  oxide. 

When  the  positive  takes  more  of  the  negative,  than  in  the  ic  com- 
pound, it  has  the  prefix  per  (from  hyper  =  more);  when  it  takes  less  of 
the  negative,  than  in  the  ous  compound,  it  takes  the  prefix  hypo  (unden). 

EXAMPLE. 

(SO  —  hypo-sulphurous  oxide). 
S  O.2  —  sulphurous  oxide. 
S  O3  —  sulphuric  oxide. 
S2O7  —  per-sulphuric  oxide. 

NOTE. — Per  and  hypo  are  sometimes  prefixed  to  the  negative  instead 
of  to  the  positive.  The  first  example  above  is  theoretical,  there  being 
no  such  free  compound.  Few  elements  form  hypo-  and  per-binaries,  and 
the  pupil  will  be  troubled  very  little  with  them.  They  are  given  here, 
so  that  if,  in  the  larger  text-books,  he  sees  hypo-  and  per- binaries  men- 
tioned, he  may  have  some  idea  of  what  is  meant. 

The  scholar  should  here  solve  many  problems,  such  as  the  follow- 
ing:— 


20  CHEMICAL  PRIMER. 

1.  Put  together  sulphur  and  antimony  to  form  two  compounds 
giving  antimony  a  strength  in  the  first  compound  as  in  the  Table,  and  in 
the  second  compound  a  strength  of  five  (which  it  sometimes  has). 
Name  one  ic,  the  other  ous. 

Am.     Sb.2  S3  —  antimonous  sulphide. 
Sb2S5  =  antimomc  sulphide. 

2.  Put  together  iodine  and  mercury,  giving  mercury  a  strength,  first, 
as  in  Table;  second,  as  in  the  parenthesis  of  Table.     Name. 

Ans.    HgI2  =  mercuric  iodide. 
Hg2 I*  —  mercurows  iodide. 

NOTE. — In  this  last  compound,  mercury  seems  to  be  a  monad,  *.  e.,  it 
seems  to  change  from  the  even  to  the  odd  strength.  A  few  of  the  other 
elements  do  the  same  thing,  as  you  will  see.  For  practical  purposes, 
this  last  formula  has  sometimes  been  written  Hg  I  =  mercurows 
iodide,  but  it  is  better  to  write  as  above. 

The  ic  and  ous  compounds  of  the  same  elements  often  differ  very 
much  in  physical  and  chemical  properties.  You  will  see,  by  looking  at 
the  samples  from  the  laboratory,  that  mercuric  iodide  is  red,  while  mer- 
curous  iodide  is  green.  Again,  carbom'c  oxide  is  not  poisonous,  while 
carbonows  oxide  is  poisonous. 

A  binary  may  be  named  by  prefixing  the  Greek  numer- 
als (mon,  di,  tri,  tetra,  etc).  In  all  cases  where  a  mistake 
would  be  likely  to  occur,  this  very  exact  method  is  used. 

EXAMPLE. 

C  O   =  =  carbon  monoxide,     (ous.) 
C  O2   =  =  carbon  di-oxide.     (ic.) 
Fe3  O4   :  =  tri-ferric  tetroxide. 
Fe2  O3   =  =  di-ferric  trioxide.     (ic.) 

NOTE. — The  older  chemists  used,  as  a  rule,  per  and  proto  for  ic  and 
ous  respectively,  as: — 

Fe  O  =  protoxide  of  iron,  instead  of  ferrous  oxide. 

Fe2  O3  =  peroxide  of  iron,  instead  of  ferric  oxide. 

Instead  of  ous,  the  prefix  sub  was  also  used,  as:  Hg,  C12  =  sub- 
chloride  of  mercury. 

Compounds,  in  which  there  were  two  of  the  positive  to  three  of  the 
negative,  often  took  the  prefix  sesqui  (one  and  one-half),  as: — 

Fe2  O3  =  sesquioxide  of  iron. 


THEORETICAL  CHEMISTRY.  21 


CHAPTER  VIII. 


Inspection  of  the  following  questions  and  the  methods 
of  solution  will  reveal  the  great  value  of  the  Atomic 
Theory  to  the  chemist,  and  indeed,  to  the  world  of 
industry. 

1.  In  116  kilograms*  of  mercuric  sulphide  (Hg  S)  how 
much  mercury? 

Hg  =   200  atomic  weight  (see  Table). 
S     =     32       " 

HgS  =   232  molecular  weight. 

232  kgs.  of  HgST=  ™d200  kgs.  of  Hg. 

1  =  ^2  of  200  kgs.  of  Hg. 

116       "  =          of  200       "      " 


of  200   =  =   100  kgs.  of  Hg.  Ans. 

-  2.     How  much  lead   chloride   (Pb  C12)  could  be  made 
from  50  grams  of  lead  ? 

Pb   =   207  at.  wt. 
C12  =      71       " 

Pb  01,  ==   278  mol.  wt. 

207  Pb  =  278PbCl2 

1   "      =  T^T  of  278  Pb  01, 
50   «    =  ^°T  of  278      " 

278 
50 


207)  13900  (67^  grams.  Ans. 
1242 

1480 
1449 

31 


"See  metric  system. 


22  CHEMICAL  PRIMER. 

It  will  be  noticed  that  there  are  two  distinct  kinds  of  questions.  The 
first  gives  the  weight  of  the  binary  and  requires  the  weight  of  the 
element.  The  second  gives  the  weight  of  the  element  and  requires  the 
weight  of  the  binary.  In  the  first  class  of  questions,  of  course,  the 
answer  is  less  than  the  given  weight.  In  the  second  class  the  answer 
is  more  than  the  given  weight.  After  obtaining  the  molecular  weight 
by  the  addition  of  the  atomic  weights,  decide  whether  your  answer  is 
to  be  greater  or  less  than  the  given  weight,  aud  arrange  the  first  equa- 
tion below  the  molecular  weight  accordingly. 

3.  From  one  metric  ton  of  the  iron  ore  hematite  (Fe2  O3,  ferric 
oxide),  how  many  kilograms  of  iron  could  be  obtained,  provided  the 
hematite  contained  25  per  cent,  of  earthy  impurities,  or  waste? 

1  M.  T.   =    1000  kgs. 
25  per  cent,  waste  leaves      75  per  cent. 

750  kgs.  of  pure  ore. 

Fe2  =  1!2  at.  wt. 
O3    =     48       " 


Fe2O3  =  160  mol.  wt. 
160Fe2O3  =  112Fe 

1      "         =  TJTFofll2Fe 
750      "         =  ^f-g  of  112  Fe  =  5£5~  kgs.  iron.  Ann. 

NOTE. — The  pupil  should  perform  very  many  problems  similar  to  the 
above.  To  show  one  common  process  of  getting  the  element  from  the 
ore,  heat  some  lead  oxide  (litharge)  on  charcoal  (carbon)  in  the  blow- 
pipe flame.  The  carbon  takes  the  oxygen  from  the  lead,  forming  car- 
bonic oxide  (C  O2)  and  leaves  the  lead  free,  i.  e.,  not  combined  with 
any  other  element  (See  Exp.  50). 

4.  How  much  lead  in  100  kgs.  of  lead  oxide  (Pb  O)?  Am.  92^f  |. 

5.  One  M.  T.  of  lead  would  make  how  many  kilograms  of  litharge? 

Am.  1077/oV- 


THEORETICAL  CHEMISTRY.  23 


CHAPTER  IX 


A  ternary  compound  is  one  having  three  different 
kinds  of  atoms  in  its  molecule. 

Most  ternaries  contain  oxygen  as  a  connecting  ele- 
ment; it  is  therefore  omitted  in  the  name.  It  is  under- 
stood to  be  the  connecting  element,  unless  otherwise  men- 
tioned (See  Chap.  XXIII).  It  is  not  omitted  in  the 
formula. 

A  ternary  is  named  by  placing  the  positive  first  and 
(the  O  being  omitted)  the  negative  last,  with  the  ending 
changed  into  ate. 

EXAMPLE. 


K  01  O3   =  potassium  chlorate. 
H2  SO4       =  hydrogen  sulphate. 

As  in  binaries,  we  have  different  compounds  of  the  same  three  ele- 
ments, and  so  must  have  different  names. 

When  the  O  is  less  (relatively  to  the  negative)  than  in  the  ate  com- 
pound, the  negative  takes  the  ending  ite. 

Rarely  the  O  may  be  less  than  in  the  ite  compound,  when  hypo 

ite  is  used.     Sometimes  the  O  is  more  than  in  the  ate-  compound,  when 
per ate  is  used. 

EXAMPLE. 

K  Cl  O  =  potassium  hypo-chlorite. 
K  Cl  O.2  =  potassium  chlorite. 
K  Cl  O>7  =  potassium  chlorate. 
K  Cl  O4  =  potassium  per-cbloraff. 


24  CHEMICAL  PRIMER. 

As  in  binaries,  the  hypo-  andper- ternaries  are  very  few  and  will  trouble 
the  student  very  little.  The  ite  compounds  are  also  few  in  comparison 
with  the  ate.  This  will  be  a  good  rule  for  beginners:  "Call  every  ternary 
an  ate,  unless  you  have  reason  to  call  it  an  ite." 

Name  the  following: — 

H3  PCX  =  ?  Mff  S(X  —    )    Which  is  the  ate  and 

,_d— -—-*  'Which     the    ite    com- 

K  NO3  -  Mg  SO3  =     j  pound? 

Ca2HO-  " 


CHAPTER  X. 


There  are  three  great  classes  of  ternaries,  with  which 
the  scholar  should  early  become  familiar,  viz. : — acids, 
bases,  and  salts. 

Acids  are  generally  sour,  and  turn  blue  vegetable  colors 
(such  as  litmus)  red. 

Bases  (those  that  are  soluble  in  water  are  called  alka- 
lies) turn  red  litmus  paper  blue. 

Acids  and  bases  are  chemical  opposites.  They  attack 
and  destroy  each  other,  forming  salts  (and  water).  This 
power  of  forming  a  salt  with  its  opposites  is  the  true  test 
for  an  acid  or  a  base.  The  test  with  litmus  paper  is  a  very 
good  one  and  usually  answers. 

NOTE. — The  pupil  should  here  test  a  number  of  acids  and  bases  with 
litmus  paper.  Of  course,  acids,  bases,  and  salts  may  exist  in  either  of 
the  three  physical  states:  solid,  liquid,  or  gaseous.  Solid  or  gaseous 
acids  and  bases  must  be  dissolved  in  water  before  testing,  or  the  litmus 
paper  wet  (which  is  the  same  thing). 

Acids,  bases,  and  salts  are  said  to  be  formed  on  the 
water-type,  thus:— 


THEORETICAL  CHEMISTRY.  25 


|  H  O  H  I   =    a  molecule  of  water. 

|  A  negative  element  OH  |  =   a  molecule   of   an 
acid. 


|  A  positive  element  OH  |  =  a  molecule  of  a  base. 


PA  positive  element  Q  a  negative  element  [  =  a 
molecule  of  a  salt. 

In  the  above  water  type,  by  a  negative  element  is  meant  one  negative 
to  hydrogen,  and  by  a  positive  element  one  positive  to  hydrogen. 

In  the  Reference  Table,  if  the  element  is  above  hydrogen,  it  is  nega- 
tive in  forming  acids,  bases,  or  salts;  if  below  hydrogen,  it  is  positive. 

Write  the  name  of  the  following,  and  mark  as  acid,  base,  or  salt. 
(Consult  Table). 

K  Cl  O^  —  potassium  chlorate  =.  salt. 
H2  S  O4     —  hydrogen  sulphate  =  acid. 

Ca  2  HO  —  calcium  hydrate  —  base. 

Na2SO4  =  ?  NaHO=: 

H  NO3  —  Mga  2  PO7  = 

KNO;=  NaClO,^ 

NOTE.  — The  division  into  positive  and  negative  elements  is  not  always 
made  at  hydrogen.     Thus,  zinc  is  usually  positive  in  forming  by  the 

water  type,  and  Zn  2  HO  zinc  hydrate— base, — but  rarely,  when  in  pres- 
ence of  a  stronger  positive  element,  as  potassium:  Zn  2  HO  zinc  hydrate 

becomes  H2  Zn  O2  =  hydrogen  zincate  =  an  acid;  and  we  have  the 


salt  K2  Zn  O2  ~=-  potassium  zincate.  So  chromium  usually  by  the  water 
3 


CHEMICAL  PRIMER. 


type  acts  as  a  negative  element,  and  H2CrO4  =  hydrogen  chromate 
—  an  acid,  but  rarely  chromium  acts  as  a  positive  element,  and  we 

+ 

have  Cr2  6  HO  =  chromium  hydrate  =  a  base.  The  pupil  at  this 
stage,  however,  should  not  attempt  to  deal  with  exceptions,  but  should 
treat  the  rule  given  as  though  it  were  absolute,  and  should  consider  all 
elements  above  hydrogen  as  negative  and  all  elements  below  hydrogen 
as  positive  in  the  formation  of  acids,  bases,  and  salts.  After  deciding 
from  the  formula,  test  all  acids  and  bases  by  litmus  paper,  and  thus 
prove  the  rule.  This  water  type  should  be  so  thoroughly  mastered,  that, 
having  the  Reference  Table  before  you,  you  can  tell  at  a  glance,  on 
seeing  the  formula,  whether  the  ternary  is  an  acid,  base,  or  salt. 


CHAPTER   XI. 


It  will  be  noticed  that  in  the  Reference  Table  four  nega- 
tive elements  and  one  compound  radical  are  linked  together. 
These  elements  are  called  the  haloid  elements  (or  halogens 
=  salt-forming),  because  they  form  salts  (and  acids)  with- 
out oxygen,  I.  e.,  they  form  binary  salts  and  acids. 

EXAMPLE. 
H  Cl  =  hydrogen  chloride  =  a  binary  acid. 

Mg  C12  =  magnesium  chloride  =  a  binary  salt. 
These  salts  and  acids  may  be  referred  to  the  water  type  by  counting 

in  the  missing  oxygen,  thus  H  Cl  =  hydrogen,  a  negf.  and  the  mis- 
sing O  =  an  acid. 


THEORETICAL  CHEMISTRY.  27 

Write  the  name,  and  mark  as  acid,  base,  or  salt,  the  following: — 

4-- 

K2  SO4  =  potassium  sulphate  =  salt. 

+  i 

K  CN  —  potassium  cyanide  =  binary  salt. 

,  j      

H4N  NO3  =  ammonium  nitrate  =  salt. 
H  I  —  ?  Mg  2  CN  = 


MgS04  = 


CHAPTER   XII. 


The  following  Reference  Table  No.  2  will  be  found  a  great  aid  in 
writing  formulas  of  ternaries.  It  is  to  be  used  in  connection  with 
Table  No.  1,  the  negative  "groupings"  in  No.  2  being  used  with  the 
positive  (to  H)  elements  in  No.  1,  and  the  positive  groupings  (all  radi- 
cals) of  No.  2  with  either  the  negative  elements  of  No.  1,  or  the  nega- 
tive groupings  of  No.  2.  The  positive  groupings  in  No.  2  being  radi- 
cals, unite  with  a  single  element  to  form  a  binary,  while  the  negative 
groupings  in  No.  2  not  being  radicals  (in  the  same  sense),  unite  with  a 
single  element  to  form  a  ternary, 

EXAMPLE. 

(C2  H5)2  O  =  ethyl  oxide  (common  ether)  =  a  binary;  but 
Mg  CO3  —  magnesium  carbonate  —  a  ternary;  and 
K  HO  =•  potassium  hydrate  =  a  ternary. 

NOTE. — H,  united  with  the  hydrate  grouping,  gives  H  HO  or  H2O 
—  hydrogen  oxide,  a  binary.  The  grouping  HO  is  often  considered  a 
compound  radical  (hydroxyl)  and  its  compound  with  an  element  is 
sometimes  named  as  a  binary.  Ex:  K  HO  =  potassium  hydroxide, 
instead  of  as  in  third  example  above. 


CHEMICAL  PRIMER. 


REFERENCE  TABLE,  No.  2. 

Qnadriralent  TRIVALENT  OR  TRIAD.  BIVALENT  OR  DYAD.  UNIVALENT  OR  MONAD. 
or  Tetrad.  A  A.  A 

GROUPIE 

NEGATIVE. 

HO   =  hydrate 

ros. 

POSITIVE. 

(Radicals.  ) 

NO8  =  nitrate 

H4N  ==  ammonium 
O2H5  =  ethy] 

01  03  =  chlorate 

02H3O2  =  acetate 

{C,  6H31O2=palmitate  >.  (  ID  Cite) 
s 

'  SO~4  =  sulphate 
SO,  =  sulphite 
CO3  =  carbonate 
C2O4  =  oxalate 
C4H4O6  =  tartrate 

C6H5  —  phenyl 
CH3  =  methyl 

GbHiii  =  amyl 

Cr  O4  =  chromate 
^  Se  O4  =•  selenate 

PO4  =  phosphate 
AsO4  —  arsenate 

C3H5  =  glyceryl  (in  fats) 

AsO3  =  arsenite 

Sb  O4  =  antimonate 

B  O3  —  borate 

C6H5O7  =  citrate 

«. 

f 

\   Si  O4  =  silicate 

P2O7  =  pyrophosphate 

THEORETICAL  CHEMISTRY. 


It  has  probably  been  noticed  that  in  the  examples  given  in  the 
previous  chapters,  all  hydrates  contain  HO,  which  acts  as  a  monad  with 
reference  to  the  elements  that  go  with  it,  also,  that  all  sulphates  con- 
tain the  dyad  grouping  SO4. 

To  write  the  formula  of  any  substance,  whose  name  is 
given,  as  potassium  carbonate,  we  first  find  the  carbonate 
grouping  in  Table  No.  2,  and  write  it  thus,  CO3//,  indicat- 
ing for  convenience  its  strength  by  the  two  marks  above. 
In  Table  No.  1  we  find  K  has  a  strength  of  one ;  placing 
this  before  the  carbonate  grouping,  we  have  K'CCV'.  But 
it  takes  two  monads  to  match  one  dyad,  therefore  we  must 
multiply  K  by  two,  and  we  have  K2CO3  for  the  formula 
required. 

Write  the  formula  for  magnesium  phosphate ; 

phosphate  grouping  =  PO4'" 

magnesium   =   Mg"; 

As   it  takes  three  dyads  to  match  two  triads,  we  have 
Mg3  2  PO4  for  the  required  formula. 

NOTE. — The  above  Table  contains  only  the  most  common  groupings. 
There  are  phosphate  groupings  other  than  the  two  mentioned;  also 
other  borate,  sulphate,  and  silicate  groupings,  etc.  For  rarer  groupings 
see  "Table  No.  2,  continued."  The  number  of  radicals,  both  negative 
and  positive,  is  countless. 


30  CHEMICAL  PRIMER. 


CHAPTER  XIII. 


Write  formulas  for  the  following,  and  mark  as  acid,  base,  or  salt: — 


potassium  arsenate  =  K  As  O4  =  salt. 

calcium  acetate  =  Ca  2  C.jH3O.2  =  salt. 

hydrogen  nitrate  =  H  NO3  =  acid. 

magnesium  hydrate  =  Mg  2  HO  =  base, 
hydrogen  silicate  —  calcium  phosphate  — 

calcium  oxalate  =  lead  chromate  — 

sodium  carbonate  —  potassium  arsenate  — 

calcium  phosphate  =  ethyl  hydrate  (common  ether)  — 

hydrogen  acetate  =  ammonium  oxalate  = 

sodium  hydrate  =  hydrogen  tartrate  — 

sodium  carbonate  —  glyceryl  hydrate  (glycerine)  — 

magnesium  phosphate  =  barium  nitrate  = 

hydrogen  citrate  =  silver  arsenite  = 

As  there  is  in  acids  but  one  element  unknown  (or  variable),  the  acids 
are  often  called  by  pet  names,  using  this  element  as  an  adjective;  thus, 
H  NO3  =  nitric  acid,  instead  of  hydrogen  nitrate. 
H2SO4  =  sulphuric  acid,  instead  of  hydrogen  sulphate. 
H^SOs  —  sulphurous  acid,  instead  of  hydrogen  sulphite. 

In  the  pet  name  of  binary  acids  both  elements  are  used;  as  H  Cl  — 
hydrochloric  acid  (or  chlorohydric),  instead  of  hydrogen  chloride. 
(H  Cl  has  still  another  pet  name  used  in  commerce,  a  commercial 
name,  muriatic  acid).  As  you  should  not  call  a  stranger  by  his  pet 
name,  so  it  is  much  better  for  you  not  to  call  any  chemical  compound 
by  its  pet  name  till  you  know  its  composition  thoroughly  and  its  chem- 
ical (systematic)  name 

Most  chemical  compounds  have  one  or  more  pet  names,  used  in  com- 
merce, by  miners,  by  workmen  in  the  arts,  by  mineralogists,  or  by 
pharmacists.  In  works  on  chemistry,  these  names  are  often  inserted 
after  the  chemical  name  (or  vice  versa). 


THEORETICAL  CHEMISTRY,  31 

If  the  molecular  composition  of  the  acids  has  been  mastered,  they 
may  be  called  by  their  pet  names  hereafter. 

Write  formulas  for  the  following:  — 

phosphoric  acid  acetic  acid 

chromic  acid  boracic  acid 

citric  acid  pyrophosphoric  acid 

hydrofluoric  acid  nitrow*  acid  (grouping  NO2) 

Inspection  of  the  following  questions  will  show  that  the  methods  of 
solution  are  the  same,  whether  the  compound  is  a  binary  or  a  ternary. 

1.  In  580  kgs.  of  the  iron  ore,  ferrous  carbonate  (Fe  CO3  spathic 
iron),  how  much  iron? 

Fe  —  56  at.  wt.  116  Fe  CO3  =  56  Fe 

C   —  12      "  1        "          -  T^  of  56  Fe, 

O3  =  48      "  580  kgs.      "    ;  -  A«o  of  56  kgs.  FC;  = 


^Tlfi  mol.  wt.  28°  k§8-—  Ans- 

2.     How  much  zinc  sulphate  could  be  made  from  130  kgs,  of  Zii? 


Zn  —  65  65  Zn  =  161 

S    —  32  1  Zn  =  ^g.  of  161  ZnSO, 

O4  =  64          130  kgs.  Zn  =  ^\°  of  161  kgs.  Zn  SO7  — 


Zn  SOl  =  161  322  kgs.—  Am. 

3.  In  100  kgs.  of  potassium  arsenate  how  much  arseiiicum? 

4.  In  150  gms.   of  mercuric  (Hg  —  dyad)  nitrate,  how  much  mer- 
cury? 

5.  In  75  gms.  of  mercuroMS  (Hg2  —  dyad)  nitrate,  how  much  mer- 
cury? 

6.  How  much  lead  carbonate  (white  lead)  could  be  made  from  50 
kgs.  of  lead? 


32 


CHEMICAL  PRIMER. 


CHAPTER  XIV. 


We  have  seen  that  chemical  changes  are  called  reactions. 
There  are  various  classes  of  reactions,  of  which  the  simpler 
should  be  thoroughly  mastered  by  beginners,  and  the  more 
complex  let  severely  alone. 

CLASS  1. 
Reaction  by  Direct  Union  (or  Separation). 

EXPERIMENT  1. — Heat  a 
small  quantity  of  sulphur 
well  mixed  with  copper  fil- 
ings in  a  test  tube  of  hard 
glass ;  a  reaction  takes  place 
and  copper  sulphw/e  is 
formed. 
Reaction:  Cu  -j-  S  =• 

copper  sulphur 

(red)  (yellow) 

CuS  (atomic  reaction) 

copper  sulphide 
(black) 

EXP.  2. — Burn  a  small 
piece  of  magnesium  ribbon 
in  the  air;  the  oxygen  of 
the  air  unites  with  the 
magnesium,  forming  mag- 
nesium oxide. 
Reaction:  Mg  -{-  O  — 

magnesium       oxygen 


Fig. 


1.  How  much  Mg  O  could  be  made  by  burning  30  gms.  of  Mg? 

2.  If  you  make  80  gms.  of  Mg  O,  how  much  Mg  must  you  take? 

Air  is  composed  of  one  part  by  volume  of  the  gas  oxy- 
gen and  about  four  parts  by  volume  of  the  gas  nitrogen, 


REACTIONS.  33 


(with  traces  of  carbonic  oxide  and  vapor  of  water,  etc.) 
Burning,  or  combustion,  is  in  general,  the  rapid  union  of 
a  substance  with  oxygen.  The  temperature  at  which  the 
substance  takes  fire,  i.  e.t  unites  rapidly  with  the  oxygen 
of  the  air;  is  called  the  igniting  point.  Of  course,  the 
product  of  the  burning  will  b>e  an  oxide. 

EXP.  3.— Burn  some  sulphur  in  a  bottle  containing  a  small  quantity 
of  water; 

Eeaction  (a):  S    -{-    O2     =     SO.; 

(a  gas) 

Close  the  mouth  of  the  bottle  and  shake; 

Reaction  (b):    SO2     +    H.2O     =     H2SO3  (an  acid). 
Test  for  the  acid  by  litmus  paper. 

EXP.  4. — Scrap_e^ some  fine  powder  from  a  piece  of  quicklime  into  a 
test  tube  of  water; 

Reaction:  CaO    -f-    H2O     =     Ca  2  HO  (a  base). 

quicklime  whter  slacked  lime 

Test  for  the  base  by  litmus  paper. 

The  last  two  reactions  reveal  the  fact  that  there  are  different  kinds 
of  oxides. 

The  two  principal  classes  of  oxides  are  :— 

1.  Acid-forming  oxides. 

2.  Basic  oxides. 

The  first  are  oxides  of  negative  elements  and  they  unite 
directly  with  water  to  form  acids,  as  in  reaction  (b)  of 
EXP.  3. 

The  second  are  oxides  of  positive  elements  (metals)  and 
unite  directly  with  water  to  form  bases,  as  in  reaction 
of  EXP.  4. 

Acid-forming  oxides  are  often  called  'anhydrides  (with- 
out water),  since  they  may  be  considered  as  acids  deprived 
of  water. 

EXAMPLE. 

SOa  =  sulphurous  anhydride. 


34  CHEMICAL  PRIMER, 


(The  older  chemists  called  the  anhydride  the  acid,  as  SO2  =  sulphur- 
ous  acid,  but  this  is  not  now  correct  usage). 

Basic  oxides  are  often  called  bases.  (It  is  important  to  know  that 
this  is  still  correct  usage.  Indeed,  some  authors  give  as  the  definition, 
"Abase  is  a  metallic  oxide, "  and  these  authors  call  the  true  base  a 
"hydrated  oxide"  or  "hydrated  base").  Basic  oxides  unite  with  acids 
to  form  salts,  just  as  the  true  bases  do.  and  by  a  reaction  very  similar. 

It  will  be  seen  that  the  term  "base"  is  used  by  chemists  somewhat 
indefinitely.  In  a  wide  sense  it  is  used  of  any  substance  that  will 
unite  with  an  acid  to  form  a  salt  (or  a  salt  and  water,  or  a  salt  with 
free  hydrogen,  etc.)  In  this  wide  sense  it  would  include: — 

1.  Positive  elements  (or  groupings). 

2.  Basic  oxides. 

3.  Positive  hydrates. 

The  word  "base"  has  been  thus  far  used  in  this  last  and  restricted 
sense.  The  word  "alkali"  is  also  used  in  a  comprehensive  sense. 
The  sense  of  the  words,  however,  may  easily  be  told  from  the  connec- 
tion. 


REACTIONS. 


35 


CHAPTER  XV. 


CLASS  2. 
Reaction  by  Change  of  Partners. 

EXP.  5. — Dissolve  one  gram  of  sodium  chloride  (common  salt) 
in  nine  grams  of  (distilled)  water  (a  ten  per  cent,  solution).  Dis- 
solve one  gram  of  silver  nitrate  (lunar  caustic)  in  nineteen  grams  of 
•water  (a  five  per  cent,  solution).  Pour  a  little  r.f  the  first  solution  into 
a  small  test-tube,  and  into  it  let  fall  a  few  drops  taken  from  the  second, 
by  means  of  a  glass  tube  dipped  beneath  the  solution  and  closed  at  the 
opposite  end  by  the  finger.  A  beautiful,  white,  curdy  solid  (silver 
chloride)  is  formed  by  the  reaction,  and  slowly  settles  to  the  bottom  of 
the  test  tube. 


Fig.  4.        (a)— lead  post,    (b)— rubber  band. 

Taking  this  reaction  as  the  type  of  its  class,  we  may 
learn  much  from  it. 


36  CHEMICAL  PRIMER. 


Just  as  by  change  of  partners, 

(  George  |  *j*   f  Charles  )  become  f  George  )  «*  /  Charles  ) 
(   Lucy  )'  '   (  Emma  }  \  Emma  )  "  "  (    Lucy  j 


so 


NaC)     -f     AgNO3     =     NaNO3     -f-    AgCl 

sodium  silver  sodium  silver 

chloride  nitrate  nitrate  chloride 

Soluble  solid  N  f       Insoluble    j 

and  therefore  /  J    solid,  called    I 

not     preeipi-  (  \     a,  jtredpi-     I 

tated,  but  re-  f  \  tate.  I 

maining     i  n  V    " 

solution.  / 

NOTE. — This  is  a  very  simple  and  frequent  method  of  reaction.  Fil- 
ter, wash,  and  preserve  all  precipitates  for  future  use  in  experiments, 
or  as  samples  of  the  various  compounds  (see  EXP.  6).  Carefully  label 
the  vials  in  which  precipitates  are  preserved.  It  will  be  noticed  that 
A§  Cl  turns  dark  when  exposed  to  the  light  (see  silver). 

Water  favors  chemical  change. 

(There  are  exceptions. — Water  does  not  favor  ordinary  combustion). 
Thus,  two  substances  in  solution  will  react  with  each  other,  which 
would  not,  if  they  were  mixed  dry.  Iron  rusts  (unites  slowly  with  the 
oxygen  of  the  air,  forming  ferric  oxide  Fe2O3)  if  exposed  to  the  air 
wet.  Knives  and  forks  must  be  wiped  dry,  else  they  rust.  Solution 
divides  a  substance  more  minutely  and  evenly  than  can  be  done  by  any 
other  method  of  mechanical  division.  Solution  separates  the  mole- 
cules. For  instance,  if  a  teaspoonful  of  common  salt  be  thrown  into  a 
barrel  of  water  and  dissolved,  molecules  of  salt  may  be  found  in  every 
drop  of  the  entire  barrel.  They  seem  to  move  among  the  molecules  of 
water  freely,  the  water  giving  them  an  atmosphere  in  which  they 
easily  perform  reactions  with  other  substances.  The  water  is  not 
written  in  the  reaction,  unless  it  really  takes  some  part  in  the  atomic 
changes. 

When  a  substance  dissolves  in  water,  and  unites  chemically  with  the 
water  to  form  another  compound  (as  in  reactions  of  EXP.  3  and  4),  this 
is  not  a  mere  solution,  but  something  more.  In  a  mere  solution  the 
substance  goes  into  the  water  (somewhat  as  grains  of  sand  might  be 
poured  into  a  measure  of  peas)  without  uniting  with  the  molecules  of 
water  at  all. 

A  gas,  as  we  have  already  learned,  may  be  dissolved  in  water  as  well 
as  a  solid. 


REACTIONS.  37 


A  liquid  may  also  be  dissolved  in  water,  but  we  speak  of  the  liquid 
not  as  dissolved  in  water,  but  as  diluted  with  water  (or  mixed)  and  we 
do  not  speak  of  the  resulting  liquid  as  a  solution  (see  OILS). 

When  as  much  as  possible  of  the  substance  is  dissolved  in  a  certain 
amount  of  water,  the  solution  is  said  to  be  a  saturated  solution. 

Many  solids  and  gases  are  insoluble  in  water.  (Some  liquids  will 
not  mix  with  water  and  therefore  cannot  be  diluted).  Often  these  may 
be  dissolved  in  other  liquids,  as  alcohol  (ethyl  hydrate),  hydrochloric 
acid,  etc.  The  liquid  dissolving  the  substance  is  called  a  solvent. 

Whenever  two  substances,  one  at  least  being  in  solution,  react,  form- 
ing a  solid  insoluble  in  the  liquid,  the  resulting  solid,  as  it  usually 
quickly  falls  to  the  bottom,  is  appropriately  called  a  precipitate.  If 
soluble  solids  are  formed  at  the  same  time,  they  of  course  remain  in 
solution.  If  gases  are  formed  in  the  reaction,  they  come  off  from  the 
liquid  in  bubbles.  Substances  which  react  with  each  other  as  in  the 
above  reaction,  especially  those  that  are  much  used  in  the  chemical 
laboratory,  are  called  reagents. 

EXP.  6. — Into  a  test-tube  containing  silver  nitrate  solution  let  fall 
a  few  drops  of  hydrochloric  acid.  The  chemicals  react  by  change  of 
partners,  as  in  EXP.  5,  thus: — 

Reaction:    H  Cl    -f    AgNO~3     -    HNO^    -f    AgCl 

hydrogen  silver  hydrogen  silver 

chloride  nitrate  nitrate  chloride 

(precipitate) 

Precipitates  may  be  separated  from  the  liquid  by  filtration.  Cut 
and  fold  some  filter  paper,  thus: — 


Fig.  5. 

and  place  it  on  a  funnel  (tunnel),  pouring  the  contents  of  the  test  tube 
upon  it. 


38 


CHEMICAL  PRIMER. 


Fig.  6.— Filter  Stand. 

The  precipitate  remains  upon  the  filter,  while  the  liquid  called  fil- 
trate (by  workmen  in  the  arts  often  called  mother  liquor),  passes 
through.  Wash  the  precipitate,  to  free  it  entirely  from  the  filtrate,  by 
forcing  with  the  breath  water  in  fine  spray  from  wash  bottles  upon  it. 
Remove  the  precipitate  and  dry  upon  glass,  or  dry  before  removing,  as 
is  sometimes  more  convenient. 


Bottle  for  cold  water. 


Fig.  7. 


Flask  for  hot  water. 


REACTIONS. 


39 


CHAPTER    XVI. 


CLASS  2.  (continued). 

EXP.  7. — Place  ierroiis  sulphide  (previously  washed  by 

gkt  in  •  water)  in   a  small  flask,   and  pour  upon  it  dilute  sulphuric 


acid. 


Reaction:    FeS    -j-    H2SO4     —    FeSO4 


H2S 


Fig.  8  —  Making  solution  of  hydrogen  sulphide. 


As  H2S  is  a  gas,  it 
comes  off  in  bubbles. 
Close  the  mouth  of  the 
flask  by  a  rubber  cork, 
through  which  a  fine, 
glass  tube  passes.  By 
means  of  a  rubber  tube 
allow  the  gas  to  pass 
into  water.  As  the 
gas  is  soluble  (three 
volumes  in  one  of 
water),  we  have  a  so- 
lution of  the  gas.  Set 
this  aside  as  a  re- 
agent. 


Caution.  —  H2S  is  a^^igt-poisonous  gas,  and  EXP.  7  should  be  per- 
formed under  a  gas  chimney,  or  near  a  window  with  an  outward  draft. 
(To  breathe  a  very  small  quantity  mixed  with  air  will,  however,  do  no 
harm).  This  gas  is  largely  used  in  the  laboratory,  and  chemists  are 
often  more  careless  with  it  than  is  consistent  with  health.  Learn  to 
be  cautious  and  careful  in  performing  all  experiments,  follovnng  direc- 
tions minutely. 

EXP.  8.  —  To  a  solution  of  lead  acetate  in  test  tube  add  drop  by  drop 
solution  of  H2S. 


Reaction:    Pb2C.2H:iO2    -f    H2S    —    PbS    -f    2HC.jH3O.2 

lead  hydrogen  lead  hydrogen 

acetate  sulphide  sulphide  acetate 

(black  precipitate) 

It  will  be  noticed,  that  when  the  hydrogen  changes  partners  with 


40  CHEMICAL  PRIMER. 

the  lead  atom  and  takes  the  acetate  grouping,  the  hydrogen  and  acetate 
grouping  being  univalent,  they  are  matched  one  to  one,  giving  us  two 
molecules  of  acetic  acid.  It  would  be  incorrect  to  write  H2  2  C2H3O2. 
Never  put  two  monads  with  two  monads  in  reactions,  but  always  one 
monad  with  one  monad,  and  if  there  be  two  of  each,  double  the 
molecule. 

Just  as  we  must  take  two  monads  to  match  one  dyad  in  a  binary,  so 
we  must  take  two  molecules  containing  monad  partners  to  react  with 
one  molecule  containing  dyad  partners.  Reagents  are  hereafter  pre- 
sumed to  be  in  solution. 

EXP.  9. — To  mercuric  chloride  (corrosive  sublimate)  add  drop  by  drop 
potassium  iodide. 

Reaction:  Hg  Cl ,    -f-    2KI     =    HgI2    -f    2  K  Cl 

mercuric  potassium  mercuric  potassium 

chloride  iodide  iodide  chloride 

(red  precipitate) 

If  too  little  is  added,  the  precipitate  dissolves;  if  too  much  is  added, 
the  precipitate  dissolves,  i.  e.  the  precipitate  dissolves  in  excess  of 
either  reagent.  Notice  that  the  molecule  of  mercuric  chloride  contains 
dyad  partners  (Hg  =  a  dyad,  and  C12  two  monads  —  a  dyad),  while 
potassium  iodide  contains  monad  partners;  therefore,  we  must  take  two 
molecules  of  the  latter  to  react  with  one  of  the  former. 

EXP.  10. — Into  a  solution  of  arsenows  oxide  let  fall  a  few  drops  of 
dilute  hydrochloric  acid. 

Reaction  (a):  As2O3    +    6  H  Cl    =     2  As  Cl      -f-    3H,O 
AsuO3,  a  molecule  containing  hexad  partners,  requires  six  molecules 
of  H  Cl  to  react  with  it.     As  C13,  arsenous  chloride,  being  soluble  in 
water,  does  not  appear  as  a  precipitate.     Into  the  test  tube  drop  solu- 
tion of  H2S. 

Reaction  (b):  2  As  C13    +    3HJ3     =    As,S3    -f    6HC1 

(lemon  yellow 
precipitate) 

In  reaction  (b)  we  must  take  two  molecules  containing  triad  partners 
(As  C13)  to  react  with  three  molecules  containing  dyad  partners  (H2S), 
just  as  we  take  two  triad  elements  to  match  three  dyad  elements  in 
forming  binaries.  In  the  second  member  of  the  equation  we  must  be 
careful  to  match  the  atoms  according  to  their  "strength"  and  to  mul- 
tiply the  molecules  afterward,  so  that  the  number  of  atoms  of  any 
element  shall  be  the  same  in  both  members. 

EXP.  11. — To  lead  acetate  (sugar  of  lead)  add  magne- 
sium sulphate. 


REACTIONS.  41 


Reaction:  Pb2C2HaO,  +  MgSO4  =  PbSO4  +  3 


insoluble  and  soluble,  but  hartn- 

therefore  harmless.  less  salt. 

(white  precipitate) 


Inspection  of  this  last  reaction  will  reveal  the  exact 
nature  of  a  chemical  antidote.  Let  the  test  tube  represent 
the  stomach.  A  chemical  antidote  is  a  substance,  which 
will  unite  with  the  poison,  forming  insoluble  or  harmless 
compounds,  or  both  (see  chap,  xxxviii). 

EXP.  12.  —  To  calcium  hydrate  (lime  water)  add  ammonium 
carbonate. 


Reaction:    Ca2HO  +  (HJN)2CO    -  CaGO    -f 

white  precipitate 
(chalk) 

Inspection  of  the  following  questions  and  the  method  of 
solving  them  will  open  to  the  attentive  student  a  wide 
field  for  careful  and  accurate  work.  To  such  a  student  the 
problems  are  not  difficult. 

1.  From  542  mgs.  of  mercuric  chloride,  how  much  mercuric  iodide 
could  be  made  by  adding  potassium  iodide? 

Reaction:  Hg  C12  +  2  K  I  =  HgI2  -f  2  K  Cl 

200  200 

71  254 

27l  mol.  wt.  454  mol.  wt. 

(will  m  ke) 

271  mgs.  Hg  CL2     -  454  mgs.  Hg  Ia 

1    "  "         --  lJfTof  454  Hgl.2 

542    "  •'         =  |4f-  of  454  mgs.  HgI2  =  908  mgs.—  Am. 

2.  How  much  mercuric  chloride  will  be  required  to  make  150  gms. 
of  mercuric  iodide  (adding  K  I)? 

Reaction:    Hg  C12  -f  2  K  I  =  Hg  I2  -f-  2  K  Cl 
200  200 

_Z1  254 

271  454 

(would  require) 

454HgLj     =    27lHgCL2 

1         "  =       4^4    °f   271    HSC1' 

150  gms.  "          r-    J!°-of271gms.  "      =  89-iff  gms.—  Ans. 

3.  How  much  potassium  iodide  would  be  required  to  make  227  gms. 
of  HgI2?:  Ana.  166  gms. 

4.  How  much  potassium  chloride  could  be  made  by  using  996  gms. 
of  potassium  iodide  ?  Ans.  447  gms. 

4 


42 


CHEMICAL  PRfMEtt. 


CHAPTER  XVII. 


CLASS  3. 
Reaction  of  Acid  and  Base. 

When  an  acid  and  base  are  united,  the  result  is  a  salt 
and  water.  The  acid  is  said  to  neutralize  the  base  (or 
vice  versa}. 

EXP.   13.  —  To  barium  hydrate  add  drop  by  drop  sulphuric  acid. 


Reaction:  Ba2HO 

base 


=  BaSO4  -f  2H2O 

salt  water 

(white  precipitate) 


EXP.  14.  —  To  oxalic  acid  add  calcium  hydrate. 


Reaction:  H2  C2  O4  -f-  Ca  2  HO  =  CaC2O4  -j-  2H2O 

acid  base  salt  water 

(white  precipitate) 

EXP.  15. — To  sodium  hydrate  add  drop    by  drop    acetic   acid,   till 
solution  is  neutral  to  litmus  paper. 

Reaction:  Na  HO  +  H  C2  H3  O2  =  Na  C,  H3  O2  -f  H2  O 

base  acid  salt  water 


There  is  no  precipitate,  be- 
cause sodium  acetate  is  soluble 
in  water. 

Filter  to  remove  any  slight 
solid  impurities  and  evaporate 
to  dryness  in  evaporating  dish 
(or  beaker)  over  a  water  bath. 
(See  Fig.  9).  Sodium  acetate, 
a  solid,  remains. 

CLASS  3  is  only  another  form 
of  CLASS  2.  In  reactions  of 
CLASS  3  the  same  law  holds 
good,  viz. :  "that  two  molecules 
containing  monad  partners 
must  be  taken  to  react  with  one  molecule  containing  dyad  partners,  etc. " 


Fig.  9.— Water  Bath. 


REACTIONS.  43 


CLASS  4. 

Reactions  of  Acids  and  Carbonates. 

In  these  reactions,  the  carbonate  grouping  breaks  up. 
When  an  acid  unites  with  a  carbonate,  the  result  is  a 
salt,  water,  and  carbonicjDxidej'a,  gas).  The  law  in 

regard  to  molecules  containing  partners  of  different 
strengths  holds  good,  as  in  the  last  two  cases.  This 
reaction  is  frequently  used  by  the  druggist  and  pharmacist. 

EXP.  16.  —  To  acetic  acid  add  sodium  carbonate  (solid  or  in  solution) 
till  effervescence  ceases.  (Effervescence  is  the  bubbling  caused 
by  the  rapid  separation  of  a  gas  from  a  liquid). 


_ 
Reaction:  Na2CO3  +  2HC;H3O.2  =  2  Na  C2H3O.j  -f-  H2O  -}-  COa 

carbonate  .   acid  salt  water          carbonic 

(soluble)  oxido 

Filter,  evaporate  filtrate,  and  preserve.  The  salt  is  obtained  as  in 
EXP.  15.  The  heat  of  evaporation  entirely  expels  any  C  O^  that  may 
be  held  in  solution  after  the  reaction. 

EXP.  17.  —  Into  dilute  citric  acid  let  fall  calcium  carbonate  till 
effervescence  ceases.  Filter,  evaporate,  and  preserve  as  before. 


Reaction:    3  Ca  CO3-f  2  H3C6H5O7=  Ca3  2  C6H5O7-j-3  H2O-{-3  CO2 

carbonate  acid  salt  water  carbonic 

oxide 

NOTE.  —  Three  molecules  containing  dyad  partners  (Ca//CO3//)  must 
react  with  two  molecules  containing  triad  partners  (H3///CeH5O7///), 
as  before. 

Notice,  in  evaporating,  that  this  salt  (calcium  citrate)  is 
less  soluble  in  hot  than  in  cold  water;  an  exception  to  the 
general  rule,  that  "for  equal  volumes,  hot  water  dissolves 
more  of  a  solid  than  cold  water." 

A.S  a  rule,  "hot  water  dissolves  less  of  a  gas  than  an 
equal  volume  of  cold  water."  Indeed,  many  gases  not 
only  will  not  dissolve  at  all  in  boiling  water,  but  may  be 
completely  expelled  from  water,  in  which  they  may  have 
been  previously  dissolved,  by  boiling  it. 


44  CHEMICAL  PRIMER. 

Before  leaving  these  chapters  on  reactions,  the  student  should  be 
able  to  write  promptly  any  reaction  belonging  to  either  of  the  four 
classes,  provided  he  has  the  names  of  the  two  substances  given  and  t/te 
two  reference  tables  before  Mm. 

MISCELLANEOUS  PROBLEMS. 

1.  Write  formulas  for  five  binary  acids. 

2.  Write  formulas  for  ten  ternary  salts. 

3.  Write  formulas  for  two  binary  salts. 

4.  Write  formulas  for  six  ternary  acids. 

5.  Write  formulas  for  five  bases. 

6.  In  150  gms.  arsenous  oxide,  how  much  As? 

7.  In  1000  gms.  of  silver  chloride,  how  much  silver? 

8.  How  much  mercuric  sulphide  could  be  made  by  using  50  kgs.  of 
mercury  (Hg/7)? 

9.  Reaction  when  phosphorus  burns  in  air? 

10.  When  carbon  burns? 

Reactions  when  the  following  are  united: — 

11.  Stannous  chloride  (Snx/)  and  hydrogen  sulphide? 

12.  Copper  sulphate  and  sodium  hydrate  ? 

13.  Sodium  carbonate  and  hydrochloric  acid? 

14.  Ammonium  carbonate  and  calcium  hydrate? 

15.  Potassium  hydrate  and  sulphuric  acid? 

16.  Calcium  hydrate  and  citric  acid? 

17.  Potassium  carbonate  and  tartaric  acid? 

18.  Acetic  acid  and  magnesium  carbonate? 

19.  To  make  190  gms.  of  magnesium  chloride*  (by  adding^  H  Cl), 
how  much  magnesium  carbonate  must  ba  taken? 

20.  How  much  arsenous  oxide,  As  ,O3  (white  arsenic)  was  contained 
in  a  vessel  full  of  water,  from  which  15  mgs.  of  arsenous  sulphide  was 
precipitated  (by  adding  H  Cl  and  H2S)? 


OXYGEN. 


45 


CHAPTER    XVIII. 


OXYG-EN. 

EXP.  18. — Carefully  pulverize  in  a  mortar  a  small  quantity  of  potas- 
sium chlorate,  and  having  mixed  it  thoroughly  with  an  equal  bulk  of 
pure  manganese  dioxide,  introduce  into  a  small  copper  retort.  Heat  by 
a  strong  alcohol  flame,  or  flame  from  a  Bunsen's  burner.  Collect  O  in 
receivers  over  a  pneumatic  tub,  as  represented  in  Fig.  JO. 


Reaction:  K  Cl  (X,     =     K  Cl    -f-    O3 


Fig.  10. — Making  Oxygen. 
(a)-retort  stand;   (b)— retort;  (u)-receiver;  (u>-pneuuiatic  tub;  (e)-receiver  removed. 

NOTE. — The  presence  of  MnO2  causes  the  O  to  come  off  more 
steadily  and  at  a  lower  temperature,  but  as  it  takes  no  part  in  the 
reaction,  it  is  not  written.  The  first  bubbles  that  come  off  are  com- 
posed principally  of  air  from  the  retort.  The  O  often  looks  cloudy, 
because  small  particles  of  the  salt  and  oxide  are  carried  over  by  the 
draft.  These  gradually  dissolve  or  settle  into  the  water.  Instead  of 
a  copper  retort  a  glass  flask  placed  on  a  sand  bath  (iron  basin  filled  with 
sand)  may  be  used.  Three  or  four  receivers  should  be  inverted,  and  as 
fast  as  filled  removed  by*means  of  a  small  cover,  holding  a  little  water, 
to  prevent  the  escape  of  the  gas.  Small  quantities  of  O  may  be  con- 
veniently made  by  using  test  tubes  as  retorts,  test  tubes,  or  bottles,  as 
receivers,  and  a  beaker  as  a  pneumatic  tub. 


46 


CHEMICAL  PRIMER. 


i  Caution.— K  Cl  Oj-Tmnrntotrfre  heated  alone.  Commercial  Mn  O.2  is 
sometimes  adulterated  M  ith  carbon  (pounded  coal)  and  when  mixed  with 
K  C1O3  and  heated,  the  mixture  explodes  violently.  The  delivery 
tube  must  be  removed  from  the  water  before  the  heat  is  taken  from  the 
retort,  otherwise  as  the  gas  in  the  retort  cools  and  contracts,  the  water 
is  forced  back  along  the  tube  by  atmospheric  pressure.  The  first  that 
falls  into  the  highly  heated  retort  is  instantly  converted  into  steam, 
causing  an  explosion.  Ordinary  care  will  prevent  any  serious  acci- 
dent. The  chief  danger  in  breaking  glass  retorts  is  to  the  eyes. 

Learn  here,  that  an  explosion  is  (generally)  caused  by  the  sudden 
conversion  of  matter  from  the  solid  or  liquid  to  the  gaseous  state. 

Oxygen  is  a  colorless  gas,  without  odor  or  taste.  As 
we  have  inferred  from  the  formulas  thus  far  used,  it  is  a 
very  abundant  element.  ]t  exists  free  (uncombined)  in 
the  air,  forming  one-fifth  its  volume.  Chemically  com- 
bined with  other  elements,  it  forms  by  weight  eight-ninths 
of  water,  one-half  of  minerals,  three-fourths  of  animal 
tissues,  and  four-fifths  of  vegetable  tissues;  in  short,  so  far 
as  we  know,  about  two-thirds  of  the  earth. 

EXP.  19. — Into  a  receiver  (bottle)  of  O,  pliwige  a  taper  having  a  live 
coal  upon  the  end,  it  immediately  bursts  into  a  blaze.  Quickly  remove 
and  blow  out  the  flame.  Repeat  the  experiment  from  twenty  to  forty 
imes,  as  may  easily  be  done  before  the  gas  is  exhausted. 


OXYGEN.  47 


Wood,  oil.  tallow,  etc.,  (things  that  we  ordinarily  burn) 
are  composed  principally  of  H  and  C,  and  are  therefore 
called  hydrocarbons.  When  hydrocarbons  (as  the  taper 
in  the  experiment)  burn,  two  reactions  take  place,  viz.  :— 

TT     -f-    O  HO    fatpamM     Gaseous 

n2  t-  \J      -  njj  (steam,  lproductllot 

p    -4-  O   PO    (f\  frfta\    f  the  corn- 

u    -h  v,  - '   uu,  (&  gas;   )  bustion> 

Immediately  after  the  O  is  exhausted,  pour  into  the  receiver  a  very 
small  quantity  of  water,  and  closing  its  mouth,  shake  at  intervals. 
The  C  O2  gradually  dissolves. 

Reaction:     CO.,,    +    H2  O     =       H2  CO3 

acid  forming  acid 

oxide 

Test  by  litmus  paper,  but  as  H2  CO3  is  a  very  weak  acid,  litmus 
paper  must  remain  a  little  time  in  it. 

O  is  a  yigorous  supporter  of  combustion.  O  is  heav- 
ier than  air,  for  we  hold  the  mouth  of  the  receiver 
upward  to  retain  the  gas. 

Water  is  the  standard  of  specific  gravity  for  solids  and 
liquids,  but  air  for  gases.  Sp.  gr.  of  air  is  1,  of  O  1.1 -K 
But  in  chemistry  hydrogen  is  made  the  standard  for 
gases. 

EXP.  20. — Straighten  a  steel  (Fe)  watch  spring  and  tip  the  end  with 
a  little  S  (kindling  wood  for  the  steel,  as  S  has  a, much  lower  igniting 
point).  Ignite  the  S  and  plunge  the  spring  into  a  receiver  of  O.  The 
steel  burns  brilliantly. 

Reaction:    Fe3    -j-    O4    =     Fe3O4 

(triferric  tetroxide, 

black  or  maiiietit; 

iron  oxide) 

As  this  oxide  of  iron  does  not  unite  with  water,  the  water  shaken  up 
in  the  receiver  has  no  effect  upon  litmus  paper.  This  reaction  is  an 
irregular  one  (strength  of  iron  apparently  not  according  to  Table). 

If  the  air  were  pure  O  undiluted  with  N,  our  iron 
stoves  would  take  fire,  and  a  general  conflagration  would 
spread  over  the  earth.  We  could  not,  for  any  length  of 
time,  breathe  pure  O,  as  it  would  so  stimulate  the  vital 


48 


CHEMICAL  PRIMER. 


processes  as  to  produce  speedy  death.  A  small  animal 
placed  in  a  jar  of  constantly  renewed  O,  dies  in  a  few 
hours. 

EXP.  21. — Charcoal  bark,  a  small  part  of  which  has  been  heated  to  a 
live  coal,  plunged  into  O  (by  means  of  a  Cu  wire  twisted  about  it), 
bursts  into  a  vivid  combustion. 


EXP.  22. — Repeat  EXP.  3  in  jar  of  O. 
(Place  S  on  chalk  in  a  combustion  spoon. 
Copper  wire  twisted  about  a  piece  of  chalk 
makes  a  good  combustion  spoon). 

EXP.  23. — Cut  under  water,  quickly  and 
carefully  dry  between  pieces  of  blotting  paper, 
a  small  piece  of  phosphorus  (not  larger  than  a 
grain  of  wheat).  Place  in  a  combustion  spoon, 
ignite  by  hot  wire,  while  lowering  into  a  large 
jar  of  O,  containing  at  the  bottom  a  little 
water.  A  blinding  light  is  caused  by  the 

combustion. 
Fig.  12. 

Reaction:     Pa     -{-     O5        =     P2<>5 

dense  white 
fiunes 

In  ;i  sh  jrt  time  these  fumes  are  dissolved  in  the  water,  and  the  follow- 


ing reaction  slowly  takes  place: — 


acid  forming 
oxide 


2H3P04 

acid 


Test  by  litmus  paper. 

Caution. — Handle  P  with  great  care,  on  no  account  touching  it. 
The  heat  of  the  hand  may  inflame  it,  and  its  burns  are  dangerous.  Its 
vapor  is  highly  poisonous,  as  is  also  its  oxide  PaO[,.  The  dense,  white 
fumes  should  be  immediately  snut  in  by  stopple  attached  to  combustion 
spoon.  (Fig.  12). 

O  is  an  exceedingly  active  gas.  It  alone  supports  all 
ordinary  burning  that  takes  place  in  the  air.  To  bring 
this  gas  in  contact  with  the  Hood  is  the  object  of  respiration 
in  animals.  The  blood  absorbs  and  carries  O  to  all  the 
tissues,  the  most  prominent  chemical  change  taking  place 
in  the  body  being  that  of  oxidativn.  (See  EXP.  57), 


HYDROGEN. 


There  is  a  peculiar  form  of  condensed  O,  called  Ozone. 
It  is  O  in  an  allotropic  state.  It  may  be  made  in  various 
ways,  especially  by  the  action  of  electricity  on  common 
O.  It  occurs  in  minute  quantities  in  the  air.  It  is  even 
more  active  than  O  and  is  a  powerful  disinfectant.  In  it 
tainted  meat  in  a  few  moments  loses  its  putrescent  odor, 
because  the  foul  material  is  oxidized,  forming  relatively 
wholesome  compounds.  The  molecule  of  ozone  may  be 

represented  thus  |  ^Q    with  three  atoms,  that  of  oxygen 
being  |  QQ  |  composed  of  two  atoms. 


CHAPTER   XIX. 


HYDROGEN. 

EXP.  24. — Place  in  a  small  flask,  or  large  test  tube,  (hydrogen  genera^ 
tor)  some  granulated  Zn.  Upon  it  pour  dilute  (10  per  cent.)  sulphuric 
acid.  Close  mouth  of  flask  with  perforated  rubber  cork,  through 
which  passes  a  nxe  glass  tube.  Collect  H  over  pneumatic  tub,  as  in 
Fig.  13. 


Zn    +    H2S04 


Fig.  IS.— Making  H)  drogen 


ZnSO;     -f    H2 

NOTE. — Collect  several  receiv- 
ers of  the  gas,  and  after  the 
reaction  has  ceased,  filter  the 
liquid  remaining  in  the  flask; 
evaporate  filtrate,  and  the 
white  salt,  zinc  sulphate,  is 
obtained.  If  a  drop  of  the 
filtrate  is  placed  on  a  piece  of 
glass  and  set  aside,  away  from 
the  dust,  beautiful  crystals 
of  the  salt  are  left  upon 


CHEMICAL  PRIMER. 


Hydrogen  is  a  colorless  gas,  without  odor  or  taste  (when 

*j     pure).     It  is  the  essential  constituent,  as  we  have  seen, 

I*-'         in  acids.     Indeed,  acids  have  sometimes  been  defined  as 

i  f  "salts  of  hydrogen."     H  does  not  exk^reg,     It  has  been 

condensed  by  cold  and  pressure,  first,  to  a  liquid  and  then 

to  arw1»tQ'solid.     H  is  not  poisonous,  but  destroys  life,  just 

as  water  does,  by  shutting  out  the  O.     The  lungs  may  be 

inflated  with  the  pure  gas  without  harm.     (Caution.— 

Gases  made  by  beginners  must  never  be  breathed.     As  a 

rule,  a  gas  is  obtained  absolutely  pure  with  great  difficulty. 

For  methods  of  obtaining  gases  pure  see  larger  text-books 

or  some  treatise).     Chemists  take  hydrogen  as  the  stand- 

ard  of   specific  gravity  for  gases.  /  With  this   standard,  j 

i^UfJL  ^"one-half  its  molecular  weight  is  the  sp.  gr.  of  any  gas"/ 

EXP.  25.  —  Remove  a  jar  of  H,  holding  the  mouth  downward,  and 
into  it  plunge  slender  lighted  taper.  The  H  takes  fire  and  burns  at 
the  mouth  of  jar,  but  the  taper  is  extinguished  in  the  gas  above.  It 
may  be  relighted  by  the  burning  H  as  it  is  being  removed. 


H  is  lighter  than  air,  for  we  Jaetfl  the  gas  by  keeping 
the  mouth  of  the  receiver  downward.  H  is  Yery  inflam- 
mable, i.  e,  its  igniting  point  is  low  It  does  not  support 
combustion  (ciLJijuliui^^ 


NOTE.  —  Combustible  bodies  and  supporters  of  combustion  are  relative 
terms.  A  jet  of  O  would  burn  in  a  jar  of  H  just  as  well  as  a  jet  of  H 
in  a  jar  of  O.  One  as  well  as  the  other,  could  be  called  the  supporter 
of  the  combustion. 

EXP.  26.  —  Pour  H  upward  from  one  test  tube  into  another,  displac- 
ing the  air.  Test  by  igniting. 

EXP.  27.—  Collect  H  from  generator  in  test  tube  by  displacement 

of  air.     Test. 

EXP.  28.  —  Attach  a  clay  pipe  (old  or  varnished)  to  generator  and 
blow  soap  bubbles  with  H.  They  ascend  and  may  be  ignited  in  the 


H  YDROGEN.  51 


Hydrogen  is  the  lightest  substance  known,  being 
about  14J  times  lighter  than  air. 

EXP.  29. — Attempt  to  blow  soap  bubbles,  using  a  new  clay  pipe  and 
letting  the  gas  come  slowly.  The  H  escapes  by  diffusion  through  the 
clay  so  rapidly,  that  the  bubbles  cannot  be  blown.  Quickly  substitute 
the  oft/ pipe  (whose  pores  are  closed)  and  the  bubbles  are  blown  with- 
out difficulty. 

All  gases  possess  power  of  diffusion,  but  the  power  is 
possessed  by  H  in  an  extreme  degree-  The  difFusibility  of 
gases  is  C1 '-inversely  as  the  square  roots  of  their  densities," 
the  density  (or  sp.  gr.)  of  any  gas  being  half  its  molecular 
weight. 

EXAMPLE. 

\/ — ^ —     \/ "  l  4  1 

U  density       *     U   density       *    *     diffusibility     •     diffusibility 
I       of  O          •      |      of  H          *    •  of  H  of  O 

That  is,  H  has  four  times  the  diffusive  power  of  O,  or  dif- 
fuses four  times  as  rapidly.  H  may  leak  through  vessels 
that  would  retain  O  permanently. 

EXP.  30. — Close  generating  flask  by  a 
rubber  stopple,  through  which  passes  a 
hard  glass  tube,  with  fine  opening.  After 
the  air  has  been  expelled  by  the  H,  ignite  the 
jet.  The  apparatus  is  the  "Philosopher's 
Lamp."  Over  the  flame  invert  a  cold, 
dry  test  tube.  It  is  bedewed  with 
moisture. 


Fig.  14.— Philosopher's  lamp.  H2     -j-     O     = 

When  H  burns,  the  product  is  water  (steam).  The  H 
flame  gives  little  light,  but  great  heat.  The  alcohol 
(ethyl  hydrate)  flame  gives  little  light  and  great  heat, 
because  alcohol  contains  much  H. 

The  flame  of  the  oxy-hydrogen  blowpipe  melts  many  substances 
(as  platinum),  infusible  in  ordinary  fire,  the  alcohol  flame,  or  the  flame 
from  a  Bunsen's  burner. 


52  CHEMICAL  PRIMER, 


Fig.  15. — Section  of  oxy-hydrogen  blowpipe. 

The  H  from  the  gasholder  is  first  turned  on  and  ignited,  and  after- 
ward the  O  is  turned  on. 

EXP.  31. — Fill  over  a  pneumatic  tub  a  stout  quart  fruit  jar  one- third 
with  O,  and  the  remainder  with  H.  Wrap  about  it  a  cloth;  remove, 
and  holding  the  mouth  downward,  quickly  ignite  by  means  of  a  taper. 
A  sharp  explosion  ensues. 

There  are  two  reports  heard  as  one,  the  second  so  closely  follows  the 
first.  The  first  is  caused  by  the  suddsn  (but  not  greater  than  a  few 
volumes)  expansion  of  the  gases  heated  by  their  union;  the  second  is 
caused  by  (the  steam  suddenly  condensing)  the  rush  of  the  air  from  all 
sides  to  fill  the  partial  vacuum.  Caution. — Of  course,  H  explodes 
when  mixed  with  air.  Care  must  b3  taken  to  expel  all  air  from  appa- 
ratus before  igniting  jets  of  H.  Never  ignite  large  quantities  of  the 
gas.  nA/V  <*v  C^/Crf  Q.  **- 

EXP.  32. — Repeat  the  experiment  of  decomposing  water  as  explained 
in  connection  with  Fig.  1. 

This  proves  by  Analysis  the  composition  of  water.  If  we  explode 
two  volumes  of  H  with  one  of  O  and  find  we  have  nothing  but  water 
left,  we  prove  the  composition  of  water  by  Synthesis. 

Water  H2O 

The  wonderful  power  of  chemical  affinity  is  shown  in 
this  compound.  A  union  of  the  most  inflammable  sub- 
stance known,  with  the  most  vigorous  supporter  of  com- 
bustion,— forms  another  substance  used  to  extinguish  fires. 
We  have  called  this  substance  by  its  pet  name,  because  it 
is  so  commpn  a  substance  and  so  generally  distributed.  Its 
systematic  name  (hydrogen  oxide)  is  seldom  used.  We 


HYDROGEN.  53 


have  already  learned  that  water  is  the  general  solvent  in 
nature,  dissolving  most  gases  and  solids  and  diluting  most 
liquids. 

Hard  water  contains  minerals  in  solution;  soft  water 
does  not. 

Hardness  produced  by  earthy  (Ca.  Mg.  Sr.  Ba.  etj.) 
carbonates  is  called  "temporary  hardness,"  because  the 
carbonate  may  be  precipitated  by  boiling,  leaving  the 
water  soft. 

EXP.  33. — Expose  on  a  deep  plate  in  the  school-room  for  24  hours 
distilled  (soft)  water.  Carbonic  oxide  (CO2)  from  the  air  dissolves  in 
it.  Shake  up  with  this  water  a  considerable  quantity  of  finely  pulver- 
ized marble  (Ca  C  O3).  Filter.  The  filtrate  is  water  of  u  temporary 
hardness."  (Carbonates  dissolve  in  water  containing  C  O2,  but  not 
in  pure  water).  Boil  in  a  deep  beaker.  The  C  O2  is  driven  off,  and  a 
white  precipitate  of  Ca  C  O3  falls.  The  "fur"  upon  the  teakettle  is  a 
precipitated  carbonate. 

Hardness  produced  by  earthy  sulphates  is  called  "per- 
manent hardness,"  because  the  water  cannot  be  made 

soft  by  boiling.  (See  SOAP). 

The  water  held  in  suspension  by  the  atmosphere  is  essen- 
tial, not  only  to  plant  life,  but  to  animal  life  as  well.  The 
earth  would  be  a  vast  desert,  were  it  not  that  tons  of  water 
are  constantly  being  carried  up  from  the  ocean  by  evap- 
oration, so  that  the  air  currents  may  distribute  it,  not 
alone  to  fall  as  rain,  but  also  to  keep  the  atmosphere  every- 
where moist. 

Many  substances,  when  they  crystallize  (assume  a  sym- 
metrical shape  in  solidifying),  take  up  a  definite  amount  of 
water,  called  water  of  crystallization.  This  may  be 
expelled  by  heat,  but  the  essential  properties  of  the  sub- 
stance are  not  changed. 

EXP.  34. — Heat  in  a  porcelain  dish  crystals  of  copper  sulphate  pre- 
viously carefully  weighed;  the  water  of  Crystallization  is  expelled 


54  CHEMICAL  PRIMER. 

and  the  blue  color  disappears.  Weigh  the  sulphate.  It  has  lost  over 
one-third  its  weight,  as  the  formula  of  crystallized  copper  sulphate  is 
Cu  S  O4,  5  H2O.  Touch  with  a  drop  of  water,  the  color  returns. 
Dissolve  in  a  small  quantity  of  water,  evaporate  slightly,  and  set  aside 
to  cool.  Beautiful  crystals  of  copper  sulphate  form  as  the  solution 
cools. 

Fine  crystals  of  various  substances  may  be  formed  in  this  way, 
viz.,  by  making  saturated  solution  of  the  substance,  slightly  evaporat- 
ing and  setting  aside  for  a  few  days.  Making  a  collection  of  crystals 
will  be  found  a  very  profitable  exercise. 

Water  of  crystallization  is  not  written  in  ordinary  reactions  of 
substances  in  solution,  but  must  be  taken  into  account  in  dealing  with 
the  dry  solids.  Of  course,  a  larger  quantity  of  the  crystallized  solid 
must  be  taken  to  equal  a  smaller  quantity  of  the  uncrystallized,  if  the 
xolid  takes  up  water  of  crystallization. 


Some  substances,  such  as  sodium  acetate  (NaCaH8O,. 
3H2O),  sodium  carbonate  (Na2CO3,  1()H2O),  etc.,  when 
exposed  to  the  air,  lose  their  water  of  crystallization  arid 
crumble  to  powder.  These  are  said  to  be  efflorescent. 


Some  substances,  as  potassium  carbonate  (K2  C  O3).  when 
exposed  to  the  air,  absorb  moisture  and  dissolve  (or  par- 
tially dissolve).  These  are  said  to  be  deliquescent. 

The  law  of  physics,  that  "heat  expands  and  cold  con- 
tracts" does  not  hold  with  water  in  cooling  from  about  4° 
(C)  to  0°,  through  which  space  it  steadily  expands,  until 
it  freezes  (crystallizes)  at  0°.  The  importance  of  this 
exception  cannot  be  over-estimated,  for  it  makes  ice 
lighter  than  water,  and  so  prevents  lakes  and  rivers  from 
freezing  solid. 

Water,  containing  impurities  in  solution,  may  be  puri- 
fied by  distillation.  The  water  is  placed  in  a  retort, 
or  "still,"  is  heated,  rises  as  steam  (at  100°),  which,  pas- 
sing through  the  condenser,  (supplied  with  cold  water  in 
direction  of  arrows,  Fig.  16),  condenses,  and  is  collected  in 


NITROGEN. 


a  receiver.  Steam  ("dry  steam")  is  an  invisible  gas. 
That  which  is  seen  and  often  miscalled  steam,  is  steam  con- 
densed (or  partially  condensed)  into  minute  globules  of 
water  and  held  in  suspension  (like  dust)  by  the  air  (or  by 
the  invisible  steam,  in  which  case  the  steam  is  called  "wet 
steam  \ 


Fig:  10.— Retort,  or  "still,"  and  condenser. 
— *•  Current  of  cold  water.  — »• 


CHAPTER  XX. 


NITROGEN. 

EXP.  35. — ^lace  a  piece  of    chalk  on  a  tripod  wire-holder,  standing 
in  a  deep  plats  of  water.      Upon  the  chalk  place  a  small  piece  of  P. 
Ignite  by  hot  wire  and  quickly  invert  a  receiver  over  it. 
P,    -f    05    =     P,05 

soluble 
white 
fumes. 


66  CHEMICAL  PRIMEli. 


The  P  unites  with  the  O  iu  the 
jar.  The  phosphoric  oxide  dissolves 
and  the  water  rises  by  atmospheric 
pressure  and  fills  one-fifth  of  the 
receiver,  the  space  before  occupied  by 
the  O.  N  remains  in  the  receiver 
above  the  water.  Leave  over  night, 
that  the  small  quantity  of  O  left, 
when  the  flame  of  P  is  extinguished, 

may  unite  with  the  remaining  P.    Of 
Fur.  17.-Making  nitrogen.  ^^   the   N   ^   obtained  ^  ^ 

pure.  Remove  receiver,  and  over  a  pneumatic  tub  fill  a  smaller  jar 
with  the  gas.  Remove  small  jar,  and  test  by  passing  a  lighted  taper 
up  into  the  gas.  The  flame  is  extinguished  and  the  N  does  not  take 
fire. 

Nitrogen  is  a  colorless  gas,  without  odor  or  taste.  It 
forms  by  volume  ^  of  the  atmosphere.  N  is  not  poison- 
ous, and  destroys  life  only  by  shutting  out  O.  It  is  not 
inflammable  and  it  does  not  support  combustion.  It 
is  a  very  inert  element.  It  dilutes  the  active  O  of  the  ajr, 
and  the  mechanical  mixture  is  thus  fitted  for  respiration. 
Some  of  its  compounds  are  by  no  means  inert.  For  example. 
"  nitro-glyeerine "  the  violent  explosive  is  glyceryl 
nitrate,  and  the  deadly  poison,  prussic  acid,  is  hydrogen 
cyanide.  No  one  can  predict  with  certainty  the  character 
of  a  chemical  compound  from  the  nature  of  its  constitu- 
ents. It  might  be  supposed  that,  N  being  lighter  than  O, 
the  air  would  separate  in  to  two  layers,  the  heavier,  O,  sink- 
ing. The  two  gases,  however,  are  kept  thoroughly  mixed 
by  the  law  of  diffusion  of  gases. 

N  forms  with  O  five  oxides,  viz. : —  • 

N2O,  hyponitrous  oxide  (acid-forming). 
N2O2  nitrogen  dioxide. 
N2O3  nitrous  oxide  (acid-forming). 
N2O4  nitrogen  tetroxide  (or  peroxide). 
N,O5  nitric  oxide  (acid-forming). 


NITROGEN.  57 


These  oxides  illustrate  well  the  great  law  of  multiple 
proportions.  When  one  substance  unites  chemically  with 
another,  it  is  in  some  definite  proportion,  or  multiple  of 
that  proportion.  Whenever  substances  are  united  phys- 
ically (mechanically,  as  in  alloys  of  metals,  etc.)  they 
may  be  united  (mixed)  in  any  proportion. 

NOTE.  —  We  see  from  the  above  that  there  is  a  third  class  of  indif- 
ferent oxides  (as  N.,O2,  N2O4),  neither  acid-forming  nor  basic.  The 
pupil  need  not  give  much  attention,  however,  to  this  class.  All  the 
positive  indifferent  oxides,  as  Mn  O.2,  Ba  O2,  K2O4,  Pb  O2,  having 
more  O  than  the  basic,  are  called  peroxides.  For  preparation  of 
N2O3  and  N.2O5  see  larger  text  books. 

EXP.  36.  —  Heat  in  flask  ammonium  nitrate  and  collect  gas  over  pneu- 
matic tub  of  warm  water. 


H4N  NO3    =     2  H2O    -|-    N2O 

Hyponitrous  oxide  ("nitrous  oxide"  "laughing  gas,") 
inhaled  with  a  small  proportion  of  O,  produces  a  peculiar 
intoxication,  hence  its  name  of  "laughing  gas."  If  the 
pure  gas  is  inhaled,  it  soon  produces  insensibility.  It  is 
•  much  used  as  an  anaesthetic  by  dentists  and  by  surgeons 
in  minor  operations.  It  is  kept  condensed  in  liquid  state 
in  iron  cylinders. 

EXP.  37.  —  To  small  pieces  of  copper  add  dilute  (25  per  cent.)  nitric 
acid,  red  fumes  appear  in  generator  (see  EXP.  38),  but  a  colorless  gas 
collects  over  the  tub. 

_  / 

Reaction  (irregular)  :  Cu3  +  8  H  N  O3  =  3  Cu  2  N  O3  -f-  4  H2  O  +  N2  O  2 

[Filter  water  in  flask,  evaporate,  and  obtain  blue  crystals  of 
'Cu8NO&]. 

EXP.  38.  —  Admit  to  test  tube  containing  N.2O2  a  bubble  of  O  (or 
air).  Red  fumes  of  N.2  O4  appear. 

N202    +    02  N2oT 

These  fumes  are  soluble  in  water,  and  the  water  slowly  rises  to  take 
the  place  of  the  dissolved  gas. 
5 


68  (CHEMICAL 


EXP.  39.  —  Into  a  small  retort  put  4  gins,  of  sodium  nitrate  (or 
K  NO3)  and  2  gms.  of  sulphuric  acid  (previously  diluted  to  90  per  cent.  ) 
Carefully  heat.  Collect  nitric  acid  (impure  and  slightly  diluted)  in  well 
cooled  test  tube,  as  in  Fig.  18. 


2HNO, 


Fig.  18. — Making  nitric  aui<l. 


EXP.  40.— Boil  quill  in  H  N  O3.     It  turns  yellow. 

EXP.  41.— To  dilute  HNOs  add  a  crystal  of  Fe  SO4;  then  add  a  few 
drops  of  H2  S  O4.  A  brown  compound  (Fe  SO4,  N.,,  Oa)  fonns  about 
the  crystal.  This  is  a  good  test  for  H  NO3. 

EXP.  42. — Throw  a  crystal  of  a  nitrate  upon  a  red-hot  coal.  The 
coal  burns  rapidly  (almost  explosively). 

Nitric  acid  (old  name  aqua  fortis)  is  a  colorless  (if 
pure),  fuming,  corrosive  liquid.  1 1  stains  organic  matter, 
as  the  skin,  nails,  etc.,  a  dingy  yellow.  It  is  a  powerful 
oxidizing  agent,  as  are  all  the  other  nitrates. 

EXP.  43. — Spread  upon  a  piece  of  copper  and  also  upon  a  piece  of  iron 
a  thin  layer  of  paraffine.  Write  a  word  upon  each  with  a  needle.  Upon 
the  writing  put  nitric  acid  (50  per  cent. )  It  etches  the  words  by  oxi- 
dizing the  metals,  dissolving  and  uniting  with  the  metallic  oxides. 


NITROGEN. 


59 


Nitric  acid  is  used  in  etching  upon  copper  and  iron 
(copperplate,  swords,  razors). 

EXP.  44.  —  Into  a  test  tube  containing  nitric  acid,  drop  a  piece  of 
gold  leaf  and  heat.  It  does  not  dissolve.  Add  a  few  drops  of  hydro- 
chloric acid.  The  gold  rapidly  dissolves,  forming  Au  C13  in  solution. 

Nitric  acid  (about  3  parts)  and  hydrochloric  acid  (5 

parts)   form  aqua  regia,  the  solvent  of  gold  (and  plat- 
inum). 

EXP.  45.  —  Place  in  a  flask  a  little  ammonium  chloride  (sal  ammoniac) 
with  an  equal  weight  of  calcium  oxide  (quicklime),  each  finely  pulver- 
ized. Add  a  few  drops  of  water  and  heat.  Dry  gas  by  passing  through 
bottle  containing  CaO.  Collect  by  displacement  of  air,  as  in  Fig.  19. 


2  H4  NCI    -f-    CaO  Ca  C12 


H,  O    -f    2H3N 


Fig.  19. 

EXP.  46  (45  concluded). — Quickly  close  mouth  of  bottle  of  ammonia 
by  perforated  rubber  cork,  through  which  passes  a  glass  tube  drawn  to 
a  fine  point.  Connect  with  water  colored  red  by  (acidulated)  litmus  and 
hasten  the  action  by  forcing  air  into  lower  flask  (at  A,  Fig.  20)  till  a 
few  drops  of  water  reach  the  receiver  of  ammonia.  The  gas  dissolves 
so  rapidly  in  the  water,  that  a  partial  vacuum  is  formed,  and  the  out- 


'60 


CHEMICAL  PJRIMER. 


side  atmospheric  pressure  produces  the    "ammonia  fountain."      The 
water  turns  blue  as  it  enters  the  receiver. 

Ammonia  is  a  colorless 
gas.  with  pungent  odor.  It 
is  much  lighter  than  air.  It 
is  very  soluble  in  water, 
700  gals,  dissolving  in  a 
single  gallon  of  water  at 
15°  (1000  +  vols.  at  0°).  It 
not  only  dissolves,  but 
unites  (H3N  +  H2O  =  H^ 
H  O)  forming  ammonium 
hydrate  ("ammonia  water," 
hartshorn,  etc.)  The  am- 
monium grouping  can  be 
passed  from  compound  to 

Fig.  20.— Ammonia  Fountain.  compound  like  an  element, 

and  hence  is  a  compound  radical.  (See  AMMONIUM).  Am- 
monia in  the  presence  of  moisture  (H4  N  H  O)  has  a  strong 
alkaline  reaction,  but  its  effect  upon  vegetable  colors  is 
only  temporary,  and  it  has  been  called  the  "volatile  alkali." 
In  concentrated  "ammonia  water"  there  is  a  large  excess 
of  the  gas  dissolved  (more  than  unites  with  the  water). 

"Evaporation  cools."  This  means,  that  when  a  substance 
evaporates,  it  absorbs  heat  from  what  is  near  by.  (See  SULPHUR  DIOX- 
IDE). Wet  one  hand  and  pass  both  hands  rapidly  through  the  air. 
The  wet  hand  is  sensibly  colder  from  the  evaporation  of  the  water. 
Pour  a  little  ether  upon  the  thermometer  bulb.  The  ether  quickly 
evaporates  and  the^mercury  falls. 

A  pressure  of  about  4J  atmospheres  J(at  0°)  converts 
gaseous  into  liquid  ammonia.  The  evaporation  of  liquid 
ammonia  produces  intense  cold  ( — 40°).  Advantageis  taken 
in  the  arts  of  this  fact  to  produce  ice  artificially. 


CARBON. 


61 


In  a  strong  generator  A  is  placed 
ice  water  saturated  with  ammonia 
gas'  (1,000  vols.  in  one).  This  is 
connected  with  an  equally  strong 
receiver  D  by  the  tube  B.  Receiver 
D  is  placed  in  cold  water.  Heat  is 
applied  to  A  and  the  great  pressure 
of  the  escaping  gas  converts  itself 
into  a  liquid  in  D.  Water  is  now 
placed  in  vessel  C.  Generator  A  is 
cooled  and  the  liquid  ammonia  in  I) 
evaporates  and  is  reabsorbed  by 
water  in  A.  The  evaporation  pro- 
duces sufficient  cold  (takes  away  or 
absorbs  sufficient  heat)  to  freeze 

water  in  C. 
Fig.  21.— Ice  machine. 

Nitrogen  and  hydrogen  do  not  unite  directly  to  form  ammonia,  but 
when  decomposition  is  taking  place  in  organic  substances  and  these  two 
elements  are  leaving  their  old  compounds,  they  unite.  Elements  just 
leaving  their  old  compounds  are  said  to  be  in  the  nascent  state,  and 
they  have  a  much  greater  tendency  to  form  new  compounds. 


CHAPTER  XXL 


CARBON. 

Carbon  is  a  very  abundant  element.  It  forms  a  large 
proportion  of  vegetable  and  animal  tissues  and  is  a  prom- 
inent constituent  of  limestone,  marble,  etc.  (carbonates). 
We  know  it  in  three  allotropic  states:— 

1.  Diamond. 

2.  Graphite  (plumbago,  black  lead). 

3.  Amorphous  carbon  (uncrystallizc<;). 


62  CHEMICAL  PRIMER. 

Graphite,  mixed  with  a  little  Sb  and  S  is  used  to  make 
common  "lead  pencils."  Mixed  with  clay,  it  makes  cruci- 
bles, the  most  refractory  (difficult  to  melt,  or  of  ores,  diffi- 
cult to  reduce)  known. 

Amorphous  carbon  (more  or  less  impure)  includes  char- 
coal, mineral  coal  (the  remains  of  vegetation  of  the  carbon- 
iferous age),  coke,  peat,  animal  charcoal  (bone  black),  soot, 
lamp  black,  and  gas-carbon. 

NOTE. — For  fuller  description  of  the  above  and  of  all  such  substances 
briefly  mentioned  in  this  primary  work,  see  the  dictionary  and  cyclo- 
paedia. Every  High  School  should  have  an  unabridged  dictionary  and 
a  cyclopaedia  placed  ivhere  scholars  can  readily  refer  to  them, 

Carbon  for  a  long  time  resists  decay.  Fence  posts  are 
charred  to  preserve  them.  Neither  acids  (except  nitric) 
nor  alkalies  affect  it. 

EXP.  47. — Collect  in  test  tube  over  mercury  (or  by  displacement  ot 
air)  H:JN.  Introduce  into  the  gas  a  piece  of  fresh  burnt,  dry  charcoal, 
mounted  on  wire  attached  to  perforated  cork,  and  quickly  dip  the 
mouth  of  test  tube  beneath  mercury.  The  Hg  rises  in  test  tube, 
because  C  absorbs  the  H  ,N  in  its  pores. 

Carbon  absorbs  many  times  its  bulk  of  gases,  condens- 
ing them  in  its  pores.  Fresh  burned  charcoal  is  a  good 
" disinfectant"  for  foul  gases.  They  are  destroyed 
within  its  pores  by  the  absorbed  O;i.e.t  by  oxidation,  (so 
that  C  is  not  a  disinfectant  in  a  strict  chemical  sense,  but 
its  action  is  mechanical).  O  is  the  real  disinfectant. 

EXP.  48. — Place  finely  pulverized  charcoal  upon  filter.  Moisten  with 
distilled  water.  Let  ink  (or  indigo  solution,  vinegar,  etc.)  fall  drop  by 
drop  upon  the  charcoal  from  an  ordinary  filter  paper  above  it.  The 
filtrate  from  charcoal  is  colorless. 

Charcoal  is  a  good  decolorizing  agent.  Animal  char- 
coal is  largely  used  in  sugar  refineries  to  remove  soluble 
impurities  and  color. 


CARBON 


EXP.  49. — Heat  upon  platinum  foil  a  piece  of  sugar  (or  organic  mat- 
ter, as  tartaric  acid,  flesh  or  vegetable).  It  chars  (turns  black,  as  the 
more  volatile  constituents  are  driven  off,  leaving  the  carbon  free). 

Charring  is  a  good  test  for  carbon  (or  for  organic 
matter). 

EXP.  50.— Upon  charcoal  put  a  little  litharge  (Pb  O).  Heat  in  the 
blow-pipe  flame.  The  O  is  taken  by  the  C,  leaving  the  Pb  free 
(uncombined). 

CO, 


2PbO    -f-    C 


Pb2 

metallic 
lead 


Carbon  is  a  good  deoxidizing  (chemical  term)  or  reduc- 
ing (mining  term)  agent.  Heated  with  the  oxides  of 
most  metals  it  deoxidizes  them,  and  is  thus  of  special  use  in 
reducing  ores  that  are  oxides  (or  carbonates,  since  great 
heat  breaks  up  the  carbonate  grouping,  setting  C  O.2  free, 
and  leaving  an  oxide  behind). 

EXP.  51. — Upon  pieces  of  marble  Ca  C  O:(  in  a  flask,  pour  dilute 
(20  per  cent. )  H  Cl.  Collect  gas  by  displacement  of  air. 


Reaction  (class  4):  Ca  C  O3  +  2  H  Cl   =  Ca  C12 


H2  O  -f  C  O2 

water  carbonic 

oxide. 


Fitr.  '22. 


64  CHEMICAL  PRIMER. 

Carbonic  oxide  (carbon  dioxide,  carbonic  anhydride, 
old  name  carbonic  acid)  is  a  colorless  gas,  with  slightly 
acid  taste.  It  is  much  heavier  than  the  air  (sp.  gr.  1.5) 
in  which  it  exists  free,  forming  yo^oi)  by  volume. 

EXP.  52.  —  Into  a  jar  of  C  O2  introduce  a  lighted  taper.  It  is  extin 
guished. 

EXP.  53.  —  Arrange  lighted  candles  along  an  inclined  trough  (piece  of 
gutter).  Pour  a  large  receiver  of  C  O2  down  the  trough.  The  candles 
go  out  in  order  as  C  O2  reaches  them. 

EXP.  54.  —  Put  a  mouse  into  a  receiver  of  C  O2.     The  animal  dies. 

Carbonic  oxide  does  not  support  combustion  and  is 

not  inflammable.  It  is  not  poisonous,  but  animals  die  in 
it  from  want  of  free  O,  that  is  from  suffocation  or 
asphyxia. 

EXP.  55.  —  Burn  Mg  ribbon  in  a  jar  of  C  Oa.  Black  particles  of  car- 
bon appear  mixed  with  the  white  oxide. 


CO,    -f    Mg2     -    2MgO      -f-    C 

white  black  , 

Dissolve  oxide  in  dilute  H  N  O3  and  C  is  made  more  distinct.  C  O^ 
supports  the  combustion  of  magnesium. 

EXP.  56.—  Into  a  jar  of  C  O2  that  has  been  tested  by  taper,  pour 
lime  water  (Ca  2  H  O),  the  water  becomes  milky.  (Or  the  gas  may 
be  passed  into  lime-water). 

Reaction   (class  3):    Ca  2  HO     -f-     C  O2    .=        CaCO3    +    H2O 

base  acid-forming  salt  water 

oxide  (white 

precipitate) 

Lime-  water  is  the  test  for  C  O2.  No  other  gas  will  (1) 
extinguish  flame  and  (2)  render  lime-water  milky. 

EXP.  57.  —  Hold  the  breath  a  short  time  and  then  expel  the  air  into 
a  receiver.  Test.  It  extinguishes  the  flame  of  taper  and  turns  lime- 
water  milky.  • 


CARBON. 


65 


Fur-  23. 


Animals  exhale  C  O2  from  the 
lungs  as  a  waste  product.  They 
use  up  O  from  the  air  and  re- 
place it  by  C  O2. 

EXP.  58. — Place  a  small  branch  with 
leaves  in  a  tall  receiver  of  water,  previ- 
ously boiled  to  expel  gases,  and  expose 
for  a  few  hours  to  direct  sunshine.  O  is 
evolved  and  collects  in  the  top  of  re- 
ceiver. Test  by  glowing  taper. 


Plants  in  sunshine  exhale  through  their  leaves  O  (except 
certain  low  orders),  using  up  C  O,  of  the  air  and  building 
the  C  into  their  tissues.  The  leaves  of  plants  correspond 
to  the  lungs  of  animals.  They  receive  the  air  through 
little  stomata  (mouths)  on  the  under  side  (principally).  The 
plant,  however,  does  much  more  through  its  leaves  than 
merely  to  respire.  It  gets  vastly  more  food  (by  weight) 
from  the  air  than  from  the  richest  soil. 

Plants  thus  purify  the  air  for  animals,  and  the  propor- 
tion of  C  O2  remains  the  same,  notwithstanding  the  enorm- 
ous yearly  combustion  of  coal.  Animals  by  a  reverse  pro- 
cess supply  from  their  own  waste  the  needed  elements  of 
plant  food. 

C  O^  tends  to  collect  in  old  wells  and  in  unventilated  portions  of 
mines.  It  is  called  by  miners  choke-damp.  Wherever  a  light  is 
extinguished  by  C  O2,  it  is  unsafe  to  go. 

EXP.  59. — Place  a  short  lighted  candle  on  a  rubber  cork  and  intro- 
duce it  into  the  bottom  of  a  vertical  glass  tube,  which  the  cork  fits. 
The  candle  goes  out.  In  the  tube  suspend  a  smaller  tube  and  introduce 
the  lighted  candle  as  before.  It  burns  steadily.  The  heated  air  (and 
C  O2)  rises  in  the  small  tube  (upward  draft)  and  the  fresh  air  contain, 
ing  O  falls  between  it  and  the  larger  tube. 

Two  openings,  at  least,  are  necessary  for  proper  ventilation.  In 
mines,  where  it  is  possible,  two  shafts,  one  at  each  end,  with  a  fire  at 


66  CHEMICAL   PRIMER. 

the  base  of  either,  answers  the  purpose.  Very  complex  arrangements, 
however,  have  to  be  made  in  many  cases  to  force  air  into  the  various 
parts  of  large  mines.  Plenty  of  fresh  air  is  the  only  preventive  to  keep 
fire-damp  (marsh  gas  C  H4)  and  C  O.2  from  accumulating  in  dangerous 
quantities. 

EXP.  60. — Hold  the  breath  a  short  time  and  then  expel  it  into  a  jar 
and  close  by  rubber  cork.  Set  aside  in  a  warm  place  for  a  day  or  two 
and  then  open.  A  very  offensive  putrescent  odor  greets  the  sweetest- 
breathed  experimenter.  (C  O2  has  no  odor). 

Churches,  school-rooms,  bed-rooms,  etc.,  should  be 
very  thoroughly  ventilated,  not  so  much  to  free  them  from 
the  injurious  CO2  as  to  remove  the  poisonous  "animal 
vapor"  (moisture  in  suspension)  thrown  off  from  the  lungs. 
This  "  vapor  "  holds  all  manner  of  organic  impurities  in 
solution. 

EXP.  61. — Fill  a  small  bottle  with  C  O2.  Close  with  the  thumb  and 
open  under  water,  pressing  the  mouth  a  few  inches  below  the  surface. 
Close  the  bottle,  remove  and  shake.  Part  of  the  C  O2  dissolves.  Open 
under  water  and  repeat  shaking.  In  this  way  the  bottle  of  C  O2  may 
be  dissolved  in  a  bottle  of  water. 

Water  at  15°  dissolves  one  vol.  of  C  O2,  but  if  the  gas  is  underpres- 
sure, it  dissolves  much  more. 

"  Soda  Water  "  is  nothing  but  a  solution  of  C  O2  under 
pressure  in  water.  It  probably  receives  its  inappropriate 
name  because  of  its  effervescence  when  relieved  of  pressure 
(like  sodium  carbonate,  "soda,"  when  mixed  with  an  acid). 

C  O2  has  been  condensed  to  a  liquid,  and  by  rapid  evaporation  of  a 
part,  the  rest  is  solidified  (frozen),  forming  a  snow-white  solid.  This 
solid  is  so  cold,  that  when  touched  it  produces  the  same  effect  as  red- 
hot  iron  (see  similar  condensation  of  S  O2). 


CARBON. 


As  we  have  seen,  COa  and  H2O 
are  the  two  great  products  of  ordi- 
nary combustion.  The  chemistry  of 
a  burning  candle  is  in  a  general  sense 
very  simple.  The  wick  is  first  raised 
to  the  igniting  point  and  the  heat 
melts  the  tallow  (composed  chiefly  of 
H  and  C  combined)  and  the  liquid 
is  then  drawn  up  by  capillary  attrac- 
tion into  the  wick.  Here  the  great 
heat  changes  the  liquid  tallow  into 
the  gaseous  state  (with  decomposi- 
tion into  various  hydrocarbons). 
Flame  is  burning  gas.  The  flame 
is  hollow,  as  no  O  can  penetrate  to 
its  center,  and  the  hollow  is  filled 
with  the  unburnt  gases.  (These  may 
be  drawn  away  by  a  fine  glass  tube 
and  burned  at  its  end,  if  the  candle  is  a  large  one).  In 
floating  outward  the  C  from  the  decomposed  hydrocarbons 
becomes  white  hot  and  gives  out  light,  but  soon  meets  the 
O  of  the  air  and  becomes  C  O2  at  the  instant  it  ceases  to 
give  light.  Outside  is  a  faintly  blue  cone  cup-shaped  at 
the  bottom  and  composed  of  burning  H  (and  C  O).  If  a 
cold  piece  of  glass  or  porcelain  is  introduced  into  the  flame 
the  C  is  lowered  below  the  igniting  point  and  is  deposited 
as  smut.  The  H2O  (steam)  is  condensed  and  deposited 
also. 

Illuminating  gas  is  made  from  bituminous  coal  by  heating  in 
retorts  and  collecting  volatile  hydrocarbons  in  a  holder.  It  contains 
various  gases,  H,  CO,  C  Ht  (marsh  gas,  "fire  damp"  of  miners), 
C2H4  (olefiant  gas,  ethylene),  C6Hfi  (vapor  of  benzol),  etc.,  and 
(before  purification)  others  that  must  be  removed,  as  H3N,  C  O2,  H2S 
(and  other  sulphur  compounds),  besides  vapor  of  "tar."  Tar  is  a  very 


-  24> 


08" 


CHEMICAL  PRIMER 


complex  substance,  from  which  the  aniline  dyes,  carbolic  acid,  etc.,  are 
obtained.  H,,  N  may  be  removed  by  passing  through  water  (or  H  Cl, 
old  method),  C  O2  by  passing  through  "pans"  of  lime  (Ca  O),  and  the 
sulphur  compounds  by  passing  over  ferric  hydrate.  The  last  reaction 
may  be  represented  thus:  — 


Fe,  6  H  O 

ferric 
hydrate 


liydui-en 
sulplmb 


ferrous 
hydrate 


a  O 


s 

free 
nlphu 


Fig.  25.— Section  of  Gas  Meter. 

The  three  arrows  represent  the  rotation 

of  the  chambers:  the  solitary  arrow  the 

escape  of    the  gas  from  chamber.    Gas 

enters  through  the  U-shaped  center. 


On  exposure  to  the  air,  ferrous 
hydrate  becomes  ferric  hydrate,  and 
the  material  may  be  repeatedly 
used  till  the  free  sulphur  forms 
from  40  to  50  per  cent.  The  tar 
vapor  condenses  and  runs  into  the 
"tar  well."  The  refuse  (coke) 
is  left  behind  in  the  retoits. 

The  purified  gas  is  measured  by 
the  meter  and  passes  into  the 
holder,  from  which  it  is  distributed 
to  consumers.  Illuminating  gas  is 
also  made  from  crude  petroleum, 
more  complex  machinery  being 
used. 


Bunsen's  Burner  is  represented  in  Fig.  9  and  is  used  when  heat, 
not  light,  is  wanted.  The  gas  is  mixed  with  the  air,  drawn  in  through 
openings  at  the  side.  The  flame  is  condensed,  is  much  hotter,  and  does 
not  smut  cold  glass. 

EXP.  02. — Heat  in  ex- 
treme tip  of  blowpipe  flame 
the  end  of  a  copper  wire. 
It  turns  black,  i.  e.,  is  oxi- 
dized, forming  Cu  O.  Heat 
in  the  midst  of  flame  nearer 
the  blowpipe.  The  CuO 
is  reduced  (deoxidized)  and 
the  bright  metallic  copper 
appears. 

By  means  of  the  blowpipe  we  may  do  two  things,  oxidize  most 
metals  (a  very  small  portion  is  sufficient  for  tests)  and  reduce  their 
oxide?. 


;.  26. 


CARBON. 


At  A  a  substance  may  be  oxidized  because  here  we  have  an  excess  of 
O  thrown  forward  from  the  blowpipe  and  highly  heated.  The  flame  at 
B  is  reducing,  for  here  there  is  an  excess  of  highly  heated  carbon 
The  reducing  flame  is  best  produced  by  holding  the  nozzle  of  blowpipe 
a  very  short  distance  from  the  flame  instead  of  in  it.  The  blowpipe 
is  a  very  valuable  instrument  in  the  analysis  of  ores. 

EXP.  63.  —  Two  inches  above  a  gas  burner  hold  a  fine  wire  gauze  and 
ignite  jet  of  gas  above  the  gauze.  It  burns  above,  but  not  below.  The 
wire  being  a  good  conductor  of  heat  reduces  the  gas  below  the  igniting 
point,  and  the  flame  cannot  pass  through  the  gauze. 


Davy's  Safety  Lamp  used  by  miners 
is  essentially  a  lamp  surrounded  by  a  wire 
gauze.  The  flame  cannot  pass  through 
this  to  ignite  the  "fire  damp"  (C  H4  marsh 
gas).  This  dangerous  gas  explodes  vio- 
lently when  mixed  with  air  and  ignited. 

EXP.  64.  —  Into  a  flask  put  a  small  quan- 
tity of  oxalic  acid  crystals  and  cover  with 
strong  sulphuric  acid.  Heat  gently  and 
pass  gases  through  wash  bottle  containing 
strong  solution  of  K  H  O.  Collect  over 
water. 


+CO'' 


The  sulphuric  acid  absorbs  H2  O  from  the  oxalic  acid  breaking  up 
the  molecule.  The  KHO  solution  absorbs  the  C  O2  becoming 
K2CO3  (and  H.,0)  and  the  CO  is  collected  in  receiver.  Test  by 
lighted  taper.  It  burns  with  bluish  flame. 

Carbonous  oxide  C  O,  (old  name  carbonic  oxide)  is  a 
colorless  poisonous  gas  formed  by  burning  C  in  a  close 
atmosphere.  Escaping  from  hot  stoves  through  the  pores 
of  the  iron  into  ill-  ventilated  rooms,  it  causes  headache.  In 
large  quantities  it  speedily  produces  coma  and  death.  The 
pale,  lambent  flame  that  plays  over  a  bed  of  glowing 
coals  after  the  brighter  flame  is  spent,  is  the  flame  of  this 
gas. 


70  CHEMICAL  PRIMER. 

NOTE. — Organic  chemistry  may  be  considered  as  carbon  continued. 
The  previous  rules  for  writing  formulas  and  names,  which  hold  so  gen- 
erally in  inorganic  chemistry,  fail  in  numberless  instances  to  meet  the 
requirements  of  organic  chemistry,  as  we  shall  see  (see  ORGANIC 
CHEMISTRY). 


CHAPTER  XXII. 


BINARY    ACID-    AND    SALT-FORMERS. 

FLUORINE,    CHLORINE,    BROMINE,    IODINE,  AND    CYANOGEN. 

EXP.  65.  —  Into  a  small  flask  on  a  sand  bath,  put  equal  weights  of 
common  salt  and  manganese  dioxide,  well  mixed.  Add  sufficient  water 
to  make  thin  paste.  Pour  in  through  funnel  a  small  quantity  of  sul- 
phuric acid  (90  per  cent.  )  and  collect  gas  in  large  test  tube  over  hot 
water,  or  by  displacement  of  air  in  deep  receivers.  Heat  should  be 
applied  to  flask  to  drive  off  the  last  (and  greater  portion)  of  the  gas. 
A  double  reaction  takes  place:  — 


_  _ 

(1)—  H.2SO4    +    2NaCl  Na2SO4    -f-    2HC1 

/ 
(2)—  MnO,    +    4HC1     -    Mn  CL,    -f-    2H,O     -f-    Cl, 

The  gas  may  be  freed  from  H  Cl  by  passing  through  wash  bottle 
(see  Fig.  27)  of  cold  water.  It  may  be  dried,  if  desired,  by  passing 
through  strong  H.j  S  O4  in  the  same  manner,  and  then  collected  by 
displacement  of  air. 

Caution.  —  Care  should  be  taken  not  to  breathe  (except  in  minute 
quantities)  chlorine,  cyanogen,  or,  in  short,  any  gases  or  products  that 
are  poisonous.  Small  quantities  of  such  gases  should  be  used  in 
experiments.  If  larger  quantities  are  desired,  they  should  be  made 
under  a  "gas  chimney,"  or  near  a  window  with  outward  draft. 


BIN  A  RY  A  CID-  A  ND  SA  L  T-FORMERS.  71 

Chlorine  is  a  greenish-yellow,  poisonous  gas  of  a  suf- 
focating odor.  When  very  dilute  it  produces  coughing 
(relieved  by  cautiously  inhaling  ammonia),  and  breathed 
in  larger  quantities  inflammation  of  the  trachea  and  bron- 
chial tubes.  It  is  2.5  times  heavier  than  air.  It  is  an 
abundant  element,  but  is  not  found  free  in  nature. 


EXP.  66. — Into  a  jar  of  Cl 
plunge  a  lighted  pitch-wood 
taper.  It  burns  awhile  with 
smoky  flame.  The  Cl  unites 
with  H  of  the  taper,  setting 
the  C  free  as  smoke.  Test  by 
blue  litmus. 

EXP.  67.— Burn  a  jet  of  H 
in  Cl  and  test  product  by  blue 
litmus. 

H  Cl  HClf 


EXP.  68. — Into  a    iar  of  Cl 

Fiij.  28. 

introduce   a  piece  of    blotting 

paper  moistened  with  frexh  and  warm  turpentine  (C10  H16).  The  Cl 
unites  with  the  H  so  vigorously  as  to  cause  it  to  take  fire,  but  the  C 
is  set  free  as  a  dense  cloud  of  smoke. 

C10Hlt;    +    Cl,,;  16HC1    -|-    CN, 

Test  by  litmus. 

01  has  a  "great  affinity  for  H.  Upon  this  affinity 
depends  its  value  as  a  disinfectant.  H  is  an  essential  con- 
stituent of  many  foul  gases.  Cl  destroys  them  as  it 
destroys  coloring  matters.  (See  EXP.  72). 

EXP.  69. — Upon  paper  containing  printer's  ink  write  with  common 
ink  (iron  tannate  Fe&C27HT,O17)  and  lower  into  a  jar  of  Cl. "  The 

common  ink  is  bleached,  but  the  printer's  ink  (linseed  oil  and  lamp 
black,  C)  is  unaffected. 

EXP.  70. —  Into  a  black  bottle  containing  cold  water  pass  Cl  gas 
(purified  of  H  Cl).  The  Cl  dissolves  (3  vols.)  and  forms  "chlorine 
water. "  Set  aside  as  a  reagent. 


72  CHEMICAL  PRIMER. 

EXP.  71. — Expose  a  test  tube  of  chlorine  water  to  the  sunlight  for  a 
few  hours.  Place  it  beside  a  test  tube  of  fresh  chlorine  water,  and  to 
each  add  a  piece  of  blue  litmus  paper.  The  fresh  chlorine  water 
bleaches,  the  other  turns  the  litmus  red.  The  light  enabled  the  Cl  to 
decompose  the  water  thus: — 

C12    +    H20     =     2HC1    +    O. 

("Light  favors  chemical  change.") 

EXP.  72. — Into  a  beaker  of  chlorine  water  let  fall  a  few  drops  of 
water  colored  by  cochineal  (or  indigo,  aniline  purple,  etc.,)  or  introduce  a 
piece  of  calico.  The  color  is  discharged. 

Chlorine  is  a  powerful  bleaching  agent,  and  for  this 
purpose  is  largely  used  in  the  arts.  It  bleaches  (and  dis- 
infects) in  two  ways: — 

1.  By  removing  H  from  the  substance. 

2.  By   removing  H  from   water  setting  free  "nascent"   O  which 
bleaches.     (Thus  Cl  bleaches  by  proxy).     Dry  Cl  does  not  bleach. 

.Bleaching  powder,  "chloride  of  lime,"  is  mixture  of  calcium 
hypo-chlorite  (Ca  2  CIO)  and  calcium  chloride  (Ca  C12).  A  dilute 
acid  sets  chlorine  free  with  promptness.  Moisture  and  exposure  sets 
chlorine  free  slowly,  therefore  bleaching  powder  is  used  as  a  disin- 
fectant. 

EXP.  73. — Into  a  jar  of  Cl,  sprinkle  antimony  (powdered  with 
a  pocket  knife).  It  takes  fire  and  fills  the  jar  with  white  fumes. 
(Sb  C15,  poisonous). 

Cl  has  a  rgreat  affinity  for  the  metals.  (Sb  is  semi- 
metal).  Most  of  them  burn  in  chlorine,  forming  chlorides. 

EXP.  74. — Into  a  test  tube  containing  a  little  common  salt,  pour 
slightly  dilute  (75  per  cent.)  sulphuric  ac'd,  and  gently  heat.  Collect 
gas,  dried  by  wash  bottle  of  strong  H2  S  U4,  in  a  small  test  tube  over 
mercury,  or  collect  in  narrow-mouthed  bottle  by  displacement  of  air. 

_  7 

2NaCl    -I-    H2S04     =     Na2SO<    +    2  H  Cl 

NOTE. — Chisel  out  of  hard  wood  a  trough  4  inches  long,  f  of  an  inch 
wide,  and  1  inch  deep.  Nail  a  lead  post  to  one  or  both  ends  to  support 
small  teat  tube.  This  makes  a  very  good  mercuric  pneumatic  tub. 


BINA RY  A CTD    AND  8 A L T-FO RMERS. 


73 


Fig.  29. —Mercuric  Tub. 


EXP.  75.  —  Introduce 
into  test  tube  of  H  Cl 
over  mercury,  a  few 
drops  of  water  by  means 
of  pipette.  The  water 
dissolves  the  gas  and  tlu; 
mercury  rises  to  take 
its  place.  A  solution  of 
HC1  in  water  remains 
above  the  mercury. 

EXP.  76. — A  fountain 
similar  to  the  "ammonia 
fountain "  of  EXP.  46 
may  be  made,  only  blue 
litmus  turns  red. 

Hydrochloric  acid,  (hydrogen  chloride,  chlorohydric 
acid,  muriatic  acid)  is  a  colorless  irrespirable,  acid  gas, 
very  soluble  in  water  (450  vols.  in  one  at  15°).  The 
liquid  called  hydrochloric  acid  is  really  a  solution  of  the 
gas  in  water  (a  mere  solution). 

EXP.  77. — Dip  a  glass  rod  into  strong  ammonia  water,  and  another 
into  strong  H  Cl  and  bring  the  rods  together.     Dense  white  fumes  of 
ammonium  chloride  appear.     Omitting  water,  the  reaction  is: — 
H3N    +    HC1  H^NCl 

This  is  a  fair  text  for  H  Cl  or  for  free  ammonia. 

EXP.  78. — Boil  in  H  Cl  a  small  piece  of  gold  leaf.  It  doys  not  dis- 
solve. Add  a  drop  of  H  N  O3,  a  yellow  solution  of  gold  chloride 
(Au  C13)  appears. 


H  Cl  and  H  N  O3  form  aqua  regia,  the  solvent  of  gold. 

EXP.  70.  —  Repeat  Exp.  5  and  6,  and  also  use  other  soluble  chlorides. 
Soluble  chlorides  precipitate  silver  as  silver  chloride. 

EXP.  80.  —  Heat  a  small  piece  of  KCib;!  upon  charcoal.     The  coal 
burns  explosively. 


2KClOa 


C3 


2KC1    -f    3CO2 


The  chlorates,  as  well  as  the  nitrates,  are  good  oxidiz- 
6 


74  CHEMICAL  PRIMER. 

ing  agents.       Potassium   chlorate   is   one   of    the   most 
important  of  the  chlorates. 

EXP.  81.  —  In  a  deep  test  tube  thoroughly  mix  a  little  pulverized 
K  Br  and  Mn  O2,  adding  H2  S  O4  (90  per  cent.)  and  gently  heating. 
The  reddish  and  irritating  fumes  of  bromine  appear.  These  may  be 
condensed  into  a  liquid  in  deep  test  tube  cooled  in  ice  water. 


(])—  H2gTix;    +    2KBr    =    K2SO7    +    2  H  Br 
(2)—  MnO,    +    4HBr     =     MnBr.    -f    2  Ha  O    -f    Bra 

Bromine  is  a  volatile,  poisonous,  dark  red  liquid,  very 
similar  in  its  properties  to  chlorine,  but  less  active.  Many 
experiments  analogous  to  those  under  Cl  maybe  performed 
with  bromine  vapor.  Thus,  Br  bleaches  and  unites  with^ 
H  to  form  hydrobromic  acid.  H  Br  and  other  soluble 
bromides  precipitate  silver  as  yellow  silver  bromide,  which 
blackens  in  sunlight  like  silver  chloride.  (Perform  experi- 
ments and  write  reactions).  Br  is  not  a  very  abundant 
element. 

EXP.  82.  —  Boil  a  very  small  piece  of  starch  (C6H10  O5)  in  water,  and 
add  a  drop  of  the  starch  solution  to  bromine  water.  A  yellow  solution 
of  bromide  of  starch  appears. 

Starch  solution  is  a  very  good  test  for  free  bromine  (see  EXP.  85). 

EXP.  83.  —  Repeat  EXP.  81,  substituting  K  I  for  K  Br,  violet  colored 
vapor  of  iodine  appears  and  condenses  as  a  solid  on  sides  of  test  tube. 

Iodine  is  a  greyish-  black  solid  with  metallic  lustre.  It 
is  a  comparatively  rare  element. 

EXP.  84.  —  To  tincture  (solution  in  alcohol)  of  .iodine  very  dilute,*  add 
dilute  solution  of  starch  paste.  Blue  iodide  of  starch  appears.  [That 
the  compound  is  not  a  very  stable  one,  may  be  shown  by  gently  heat- 
ing. The  blue  color  disappears  (if  solution  was  dilute),  but  reappears 
as  the  solution  cools], 

Starch  is  a  very  delicate  test  for  free  iodine  (See  EXP.  85).  Soluble 
iodides  precipitate  silver  as  silver  iodide  which  blackens  in  sunlight. 

EXP.  85.  —  Into  a  test  tube  put  solution  of  K  Br,  and  into  second 
test  tube  K  I.  Add  to  each  two  or  three  drops  of  starch  solution. 


BINARY  ACID-  AND  SALT-FORMERS.  75 

N o  yellow  or  blue  color  appears,  because  the  Br  and  I  are  combined 
with  K.  To  each  add  one  drop  of  chlorine  water.  The  yellow  and 
the  blue  colors  appear  because  the  Cl  Unites  with  the  K  setting  the  Br 
and  I  free. 

(1)— K  Br    -f    Cl    =     K  Cl    -f    Br  (free). 
(2)— K I        -f    Cl    =     K  Cl    -f-        I  (free). 

The  free  Br  and  I  then  unite  with  the  starch  forming  the  yellow  and 
the  blue  color  respectively. 

This  experiment  shows  the  superior  cliemism    (chemical  affinity) 
or  activity  of  chlorine. 


Fluorine  is  the  only  element  which  does  not  unite 
chemically  with  oxygen.  It  is  supposed  to  be  a  colorless 
gas,  but  so  great  is  its  chemical  affinity  that  it  has  not 
been  satisfactorily  isolated  (set  free). 

EXP.  86.  —  In  a  platinum  or  lead  crucible  plase  two  grams  of  Fluor 
Spar  (Ca  F2)  and  cover  with  strong  H2  S  O4.  Coat  a  piece  of  glass 
at  a  gentle  heat  with  beeswax,  and  having  written  with  a  zinc  point 
(which  will  not  scratch  the  glass)  a  word  upon  the  wax,  gently  heat 
crucible,  and  removing  lamp,  cover  with  glass.  Leave  over  night.  The 
word  is  etched  upon  the  glass. 


(1)—  CaF2    -f    H,S04    =     CaSO;    -f    2  H  F 
(2J-4-HF    -f    SiO2    =     2H2O    -f    Si  F. 

of  the    _ 
glass  (Na4  Si  04) 

Hydrofluoric  acid  (H  F)  is  used  for  etching  letters  or 
beautiful  designs  upon  glass.  If  the  gas  is  used  the  letters 
or  designs  are  left  rough  ;  but  if  a  solution  of  the  gas  in 
water  (kept  in  gutta  percha  bottles)  is  used,  the  etched 
portion  is  smooth. 

EXP.  87.  —  In  a  tube  of  hard  glass  place  a  small  quantity  of  mercuric 
cyanide  (Hg  2  C  N).  Heat  carefully  to  dull  redness  and  collect  gas  in 
test  tube  over  mercury.  Test  by  lighted  taper.  The  gas  burns  with 
reddish-purple  flame. 


_ 

(1)—  Hg2CN    =    Hg    -f-    (CN)a 

(2)-CN    +    O,    =    CO, 


H 


76  CHEMICAL  PRIMER. 


Cyanogen  (<J  JSI  or  Cy)  is  a  colorless,  pungent,  inflam- 
mable gas  with  strong  peach-blossom  odor.  As  the  mole- 
cule of  hydrogen  has  been  represented  thus  |  H  H  |,  so 
the  molecule  of  free  cyanogen  may  be  represented  thus 


It  is  interesting  as  being  the  first  ' '  compound  radical "  isolated. 
It  forms  binary  salts,  several  of  which  are  very  important.  The 
intensely  poisonous  prussdc  acid  (hydrogen  cyanide,  H  C  N)  may  be 
formed  by  the  action  of  sulphuric  acid  on  potassium  cyanide.  (Do  not 
perform  the  experiment). 


2KCN    -f    H,S04     =    K,S04    -f-    2HCN 


CHAPTER   XX1I1. 


NORMAL  SALTS,   ACID  SALTS,  ETC. 

A  normal  salt  (old  name  neutral  salt)  is  one  which  is 
formed  by  replacing  all  the  replaceable  hydrogen  of  the 
acid  by  a  positive  element  or  grouping. 


EXAMPLE. 


H2  C4  H4  O,;  =  hydrogen  tartrate  =  acid. 

Ka  C4  H4  O6  =  potassium  tartrate  =  normal  salt. 

NOTE. — Hitherto  by  salts  have  been  meant  normal  salts. 

An  acid  salt  is  one  which  is  formed  by  replacing  only 
part  of  the  replaceable  hydrogen  of  the  acid^by  a  positive 
element  or  grouping. 


NORMAL  SALTS,  ACID  SALTS,  ETC.  77 

EXAMPLE. 

H2  C4  H4  O6  =  hydrogen  tartrate  =  acid. 


Acid  salts  usually  turn  blue  litmus  red,  but  this  is  by  no  means 
universal.  In  EXP.  39,  if  one-half  as  much  sodium  nitrate  be  taken, 
with  strong  sulphuric  acid,  an  acid  salt,  instead  of  a  normal  salt 
results. 


NaN7>T    H-    H2SO4    =    HNaSO~    -f- 

acid 
sodium 
sulphate 

In  general,  by  adding  an  excess  of  the  acid  (which  is  the  same  as 
taking  less  of  the  other  substance),  an  acid  salt  may  be  obtained.  Acid 
salts,  as  a  rule,  react  with  carbonates  like  acids,  that  is,  forming  a  salt, 
(normal),  water  and  carbonic  oxide,  as:  — 

2HKC4H406  -f-  K.CO3  =  2K2C4H4O6  +  H,O  -f-  CO, 

acid  salt  carbonate  normal  water  carbon 

salt  dioxide 

A  double  salt  is  one  which  is  formed  by  replacing  part, 
or  all  of  the  replaceable  hydrogen  of  the  acid  by  two  posi- 
tive elements  or  groupings. 

EXAMPLE. 


H2  C4  H4  O6  =  tartaric  acid. 


K  Na  C4  H4  OK  =  potassium  sodium  tartrate  =  double  salt. 
("Rochellesalt") 


H3  P  O4  =  phosphoric  acid. 

H  Na  H4  N  P  O4  —  hydrogen  sodium  ammonium  phosphate  = 
double  salt  (microcosmic  salt).  A  dauble  salt  may  be  at  the  same  time 
an  acid  salt,  like  the  last. 

A  double  salt  may  be  formed  by  an  acid  salt  of  one  metal  acting  on 
the  carbonate  of  the  other,  thus: — 

X 

Na2  C  O3  +  2  H  K  C4  H4  O6  =  2  K  Na  C4  H4  O6  -f-  H^  O  -f-  C  O3 

sodium  acid  double  water          carbonic 

.carbonate  potassium  salt  oxide 

tartrate 

Acids  containing  one,  two,  three,  etc.,  atoms  of  replaceable  hydro- 
gen are  said  to  be  respectively  monobasic,  dibasic,  tribasic,  etc. 


78  CHEMICAL  PRIMER. 

EXAMPLE. 

H  NO3  ='  mono-basic  acid. 


H2  S  O4  —  dibasic  acid. 

H3  P  O4  —  tribasic  acid. 

H4  SiO4  —  tetrabasic  acid. 

NOTE. — A  tribasic  acid  may  form  twy  acid  salts,  as: — 


H2NaPO1  —  dihydrogen  sodium  phosphate  —  acid  salt. 
H  Na2  P  O4  =  hydrogen  disodium  phosphate  =  acid  salt. 

A  basic  salt  is  one  which  may  be  formed  by  replacing 
one  or  more  hydrate  groupings  of  the  base  by  a  negative 
grouping.  (This  definition  is  a  narrow  one,  covering  most 
but  not  all  basic  salts). 

EXAMPLE. 

Pb  2  HO     —     lead  hydrate     —     base. 

Pb  HO  NO3     =     lead  hydro-nitrate     =     basic  salt. 

Al.jSHO     =     aluminum  hydrate     =     base. 

A12  2  H  O  Si  O ,     =     alumnium  hydro-silicate     =     basic  salt. 

Sulph-  and  Selen-acids  and  salts.  In  all  formulas  for 
ternaries  thus  far  used,  oxygen  has  been  the  last  element. 
It  is  supposed  to  be  principally  a  linking  or  connecting 
element.  Now  there  are  a  few  other  dyad  elements  that 
can  perform  this  office  of  linking,  especially  sulphur  and 
selenium.  To  write  the  formula  for  a  sulph-  or  a  selen- 
acid  or  salt,  the  same  reference  table  may  be  used,  only 
sulphur  or  selenium,  as  the  case  may  be,  must  be  substi- 
tuted atom  for  atom,  in  place  of  oxygen. 

EXAMPLE. 

K^C  O3  —  potassium  carbonate  =  salt. 

K2  C  S3  =  potassium  sulpho-carbonate  ='  sulph-salt. 

Ag3  As  O4  =  silver  arsenate  =  salt. 

Ag3AsS4  —  silver  sulph-arsenate  =  sulph-salt. 

K3SbO3  =  potassium   antimonite  —  salt. 

K3  Sb  Se3  =  potassium  selen- antimonite  =  selen-salt. 


NORMAL  SALTS,  ACID  SALTS,  ETC.  79 


H3  As  84  =  hydrogen  sulph-arseiiate  —  sulph-acid. 

NOTE. — Instead  of    sulph-,   thio-  (Greek  thion,  sulphur)  is  used  by 
some  chemists,  as  K2  C  S3  —  potassium  thio-carbonate. 

The  sulph-  and  sel en-acids  and  salts  are  few  compared  to  those  con- 
taining oxygen. 

MISCELLANEOUS    QUESTIONS. 

1.  Reaction  in  making  O  ? 

2.  How  many  litres  of  O  can  be  made  from  150  grains  of  K  Cl  O3Y 
(NOTE.— A  litre  of  H  weighs  .0896  grams  (at  Oc  and  barometer 
760mm),  and  a  litre  of  O  weighs  16  times  as  much,  a  litre  of  N  14  times 
as  much,  etc. ,  accordi  ng  to  the  atomic   weight  of  the  gas.     To  find  the 
weight  of  compound  gases,  multiply  th».  weight  of  H  by  one-half  the  mo- 
lecular weight  of  the  g<is.  Ex. — A  litre  of  C  O2  weighs  22  times  .0896 
gms.). 

3.  Tell  what  you  know  about  O  (ten  lines). 

4.  Give  experiments  proving  the  character  (properties)  of  O 

5.  Reaction  in  making  H  ? 

6.  How  many  litres  of  H  could  be  made  by  using  5  grams  of  Zn? 

7.  How  many  grams  of  Zn  must  be  u^ed  to  make  15  litres  of  H? 

8.  Give  properties  of  H  and  prove  by  detailing  experiments. 

9.  What  is  a  deliquescent  salt?     An  efflorescent  salt? 

10.  How  was  N  obtained? 

11.  Give  the  composition  of  air. 

12.  What  was  proved  by  the  "ammonia  fountain  "  ? 
J3.  What  is  "aqua  regta"  ?  and  why  so  called? 

14.  AVhat  is  meant  by  "nascent"  hydrogen? 

15.  Give  EXP.  proving  that  C  is  a  good  decolorizing  agent. 

16.  Give  EXP.  showing  ih&t  fresh  burned  C  is  good  "  disinfectant." 

17.  How  may  C  O2  be  made? 

18.  Fifty  litres  of  C  Oa  could  be  made  by  using  what  quantity 
(grams)  of  Mg  C  O3? 

19.  Detail  three  experiments  under  carbonic  oxide. 

20.  Animals  and  the  higher  orders  of  plants  differ   with  respect  to 
use  of  C  O2  and  O.     How  ? 

21.  Write  5  lines  about  chlorine,  saying  the  most  possible. 

22.  Ho\v  is  glass  etched?     Copper  and  iron? 

23.  What  is  cyan  ogen?     And  why  is  it  treated  in  the  chapter  on 
chlorine,  bromine,  etc.,  rather  thai  under  nitrogen  or  carbon? 

24.  Write  formulas  for  three  acid  salts,  tvvo   basic   salts   and  one 
double  salt.     (Use  REFERENCE  TABLES). 

25.  Write  formulas  for  two  sulph-salts,  one  sulph-acid  and  two  selen- 
salts. 


80  CHEMICAL  PRIMER, 


CHAPTER  XXIV. 


SULPHUR    AND    PHOSPHORUS. 

Sulphur  is  found  free  (native)  in  volcanic  regions',  It 
is  found  combined  in  cinnabar,  (Hg  S)  iron  pyrites  (-Fe  B2);. 
galena  (Pb  S),  blende  (Zn  S)  etc.  It  is  contained  in  most- 
animal  tissues  and  especially  in  the  perspiration  and  hair, 
also  in  many  vegetables,  especially  in  those  that  are  strong- 
smelling. 

EXP.  88. — Drop*  a  bright  silver  coin  upon  white  of  egg  and  leave 
ovi-r  night.  Tt  is  blackened. 

Eggs  contain  sulphur  and  so  tarnish  silver  spoons,  blick  silver  sul- 
phid  •••  (Ag2  S)  being  formed. 

EXP.  8). — Into  a  dilute  solution  of  lead  acetate  introduce  white 
horse-hairs  (also  into  silver  nitrate  solution).  Leave  over  night.  They 
are  colored  black. 

Many  "hair  dyes"  contain  salts  of  lead  or  silver.  The  metal  unites 
with  S  of  the  hair,  forming  black  Pb  S,  or  black  Ag2  S.  Such  hair 
dyes  are  highly  injurious. 

Sulphur  exists  in  several  allotropic  states,  among  which  are  (1)  the 
crystallized,  (2)  the  common  uncrystallized  ("amorphous"),  and  (3)  the 
plastic  (viscid,  also  uncrystallized). 

EXP.  90. — Melt  S  and  let  cool.  Crystals  form  at  the  bottom  of  the 
liqoid.  Dissolve  brimstone  in  carbon  disulphide  (CS2),  allow  to  evap- 
orate over  night.  Crystals  of  S  are  left  (see  chap.»:xxiii). 

EXP.  91. — Heat  sulphur  for  about  five  minutes,  or  till  melted  mass 
at  first  thick  becomes  thin.  Quickly  pour  into  cold  water.  Plastic  S 
results.  This  form  is  unstable  and  becomes  brittle  in  a  few  days, 

EXP.  92. — In  a  small  tube  of  hard  glass  closed  at  one  end  heat  iron 
pyrites  (Fe  S2).  Part  of  the  sulphur  sublimes  and  condenses  on  cold 
part  of  the  tube. 


SULPHUR. 


HI 


3FeS2     —    E3St    -f    S; 

NOTE.— A  substance  sublimes  when  it  rises  as  a  vapor  and  condenses 
as  a  solid.  A  substance  distills  when  it  rises  as  a  vapor  and  condenses, 
as  a  liquid. 

S  is  obtained  from  Iron  pyrites  by  "roasting  "  the  ore  and  condemn 
ing  the  S. 

EXP.  93. — Repeat  EXP.  3,  placing  in  the  bottle  a  red  rose.  The  rose 
is  bleached.  Immerse  in  dilute  sulphuric  acid,  the  color  is  restored. 

Sulphur  dioxide  is  used  in  bleaching  silk,  straw  and 
woolen  goods  which  would  be  injured  (turned  yellow)  by 
chlorine.  Colorless  compounds  are  formed  by  the  union 
of  the  S  O,  with  the  coloring  matter,  but  the  reaction  is 
complex. 

S  O2  is  also  an  antiseptic.  S  burned  in  a  vessel  pre- 
vents the  fermentation  of  the  liquid  (as  new  cider)  after- 
wards put  in.  Like  all  strong  antiseptics  it  is  poisonous. 

EXP.  94. — Place  in  a  small  flask  (provided  with  safety  tube  as  in  FIG. 
22,  or  as  in  H2  S  generator  in  FRONTISPIECE  2)  pieces  of  copper  foil  (or 
wire)  and  add  as  much  strong  H2  S  O4  as  will  not  quite  qover  the  cop- 
per. Carefully  heat  until  gas  begins  to  be  evolved  and  then  remove 
heat;  else  the  liquid  froths  from  too  violent  reaction. 


Cu 


CuS04     -f    2H,  O     -f    SO. 


2H2S04    = 

Pass  through  small  con- 
denser and  connect  conden- 
ser \vith  apparatus  (S  O2 
condenser)  shown  in  FIG. 
30,  which  is  immersed  in  a 
freezing  mixture  (ice  and 
salt).  S  O2  is  easily  .con- 
densed by  "cold"  to  a  liquid. 
Turn  stop-cocks  and  pre- 
serve. 

Wire  stop-cocks  (.FiG.  31)  on  rubber  connectors  (boiled  in  paraffine); 
may  be  used  in  place  of  glass  stop-cocks.  S  O^  may  also  be  condensed' 
in  strong  glass  tube  (drawn  to  a  point  at  one  end)  by  pressure  of  a 


Fi?.  30.— S  O2  Condenser. 


82 


CHEMICAL  PRIMKlt. 


plunger  with  close  fitting,  greased  rubber  head.  When  pressure  (at 
15°)  reaches  one  and  one-half  atmospheres,  drops  appear  on  the  side, 
and  liquid  S  O.2  gathers  in  the  lower  part  of  the  tube.  If  plunger  is 

quickly  withdrawn  a  part  is 
frozen  (by  cold  produced  by 
sudden  evaporation)  into  a  snow- 
white  solid. 

Place  water  in  small  platinum 
or  other  thin-walled  disli  and 
pour  around  it  a  little  liquid 
SO2.  Blow  with  bellows  to 
hasten  evaporation  of  S  O.2. 
The  rapid  vaporization  pro- 
duces a  cold  ( — 50°)  so  great 
Fig.  31.-Spring  Stop-Cock.  (absorbs  so  much  heat)  that  the 

water  is  quickly  frozen.  Mercury  may  be  frozen  if  used  instead  of 
water.  If  S  O.2  be  evaporated  in  the  receiver  of  an  air-pump,  a  part 
will  be  solidified  (frozen)  forming  snow-like  solid. 

EXP.  95. — Burn  S  in  a  large  jar  and  pass  into  it  H2  S  (See  EXP.  7). 
The  bottom  of  the  jar  is  covered  with  sulphur. 

SO.    -j-    2H2S    =    S3    +    2H20 

This  illustrates  the  formation  of  native  sulphur  in  volcanic  regions,  as 
volcanic  gases  contain  S  O2  and  H2  S. 

EXP.  96. — Burn  S  as  in  EXP.  3,  and  quickly  stir  with  glass  rod,  upon 
the  end  of  which  is  twine  wet  with  strong  H  N  O3.  (Nitrates  are  good 
oxidizing  agents,  we  have  learned).  The  S  O2  takes  O  from  the  nitric 
acid,  becoming  S  O3  sulphuric  oxide  (anhydride).  Shake  up  with 
water. 

S03    +    H20    =    H2S04 

Test  water  with  barium  chloride,  the  test  of  sulphuric  acid  (and  sol- 
uble sulphates). 

HjSd;    +    BaCl2    —    BaSOj    -f    2HC1 

white  precipitate 

Sulphuric  acid,  (k'oil  of  vitriol")  is  an  oily  liquid  (sp. 
gr.  1.84).  It  is  the  most  important  of  the  acids  and  is 
used  in  preparing  numberless  other  substances,  especially 
acids. 


SULPHUlt.  83 


The  experiment  illustrates  its  preparation. 

SO.,  from  burning  sulphur  is  carried  into  large  leaden  cham- 
bers, whose  floors  are  covered  with  water.  Into  these  air  and 
nitric  acid  fumes  are  admitted.  The  N2  O4  from  the  nitric  acid  acts  as 
a  carrier  of  O  from  the  air  to  the  S  O2  (see  EXP.  38). 

2SO2    -f    N2O4    -    2SO3  .  H-    N2O2 

/ 
N202    -f-    O2    =    N204 

from 
the  air 

The  dilute  acid  is  evaporated  in  leaden  pans,  till  it  begins  to  attack 
the  lead.  (Commercial  H2  S  O4  contains  Pb  S  O4,  which  falls  as 
white  precipitate  when  the  acid  is  diluted).  It  is  then  removed  and 
concentrated  in  glass  or  platinum  stills. 

EXP.  97. — Into  a  beaker  containing  water  pour  twice  its  volume  of 
strong  H2  S  O4.  Great  heat  is  developed. 

EXP.  98.— Upon  white  sugar  (Cn  H22  On)  (starch  or  wood  C6  H]9  O5) 
pour  strong  sulphuric  acid.  It  chars  by  removing  the  elements  of  water, 
leaving  the  black  carbon  free.  Evaporate  dilute  H2  S  O4  upon  white 
paper.  As  the  acid  increases  in  strength,  the  paper  chars. 

Concentrated  sulphuric  acid  has  a  great  affinity  for 
water.  It  is  used  for  drying  gases  with  which  it  does  not 
react.  Care  must  be  taken  in  diluting  the  acid,  to  mix  in 
a  vessel  that  will  stand  the  heat.  (In  diluting  heavy 
liquids,  pour  the  liquid  into  the  water,  (not  water  into  the 
liquid). — "Fuming  sulphuric  acid"  is  a  solution  of  S  O3  in 
H2SO, 

EXP.  99. — Into  a  solution  (slightly  acidulated  with  H  Cl)  of  salts  of 
lead,  copper,  bismuth,  mercury  (ic)  cadmium,  arsenicum,  antimony,  and 
tin  respectively  in  test  tubes,  also  into  Zn  salt,  to  which  a  few  drops 
of  ammonium  hydrate  have  been  added,  put  solution  of  H2  S.  Reac- 
tion by  change  of  partners  throws  down  sulphides.  Pb  S  black,  Cu  S 
black,  Bi2  S3  black,  Hg  S  white,  yellow,  reddish-brown,  and  finally 
black,  CdS  yellow,  As2S3  lemon  yellow,  Sb.2  S3  orange,  SnS 
brownish-black,  Sn  S2  yellow. 

Hydrogen  sulphide  (H2  S  "sulphuretted  hydrogen")  is 


84  CHEMICAL  PRIMER. 

much  used  in  the  laboratory  to  precipitate  metals,  as;  sul- 
phides (see  ANALYTICAL  CHARTS).  H,  S  is  readily  inflam- 
mable, as  may  be  shown  by  igniting  in  test  tube. 

Carbon  disulphide  (C  S,)  a  volatile,  colorless,  inflam- 
mable liquid,  may  be  produced  by  passing  sulphur  over 
red-hot  coals.  It  is  an  excellent  solvent,  dissolving  readily 
S,  P,  I,  and  many  organic  substances.  It  refracts  light 

powerfully,  and  hence  is  often  used  in  filling  prisms. 

The  rare  element,  Selenium,  in  many  respects  resembles  sulphur. 


Phosphorus  is  a  semi-transparent,  nearly  colorless,  wax- 
like  solid.  It  is  kept  underwater  in  "sticks,"'  as  it  slowly 
oxidizes  in  the  air  and  takes  fire  at  a  very  low  tempera- 
ture. It  is  highly  poisonous.  Its  vapor  breathed  (in  more 
than  minute  quantities)  produces  ulceration  of  the  jaw, 
cured  with  difficulty  (see  CAUTION,  EXP.  23). 

Another  variety,  red  or  amorphous,  is  known.  This  differs  widely 
from  ordinary  P.  It  does  not  emit  the  "jaw-poisoning  fumes"  and 
can  be  safely  handled.  P  in  this  allotropic  state  may  be  prepared  by 
heating  ordinary  phosphorus  in  a  closed  vessel. 

Phosphorus,  because  of  its  low  igniting  point,  is  largely 
used  in  the  manufacture  of  matches.  The  wood  of  the 
match  is  first  dipped  in  melted  sulphur,  then  into  paste  of 
P,  potassium  nitrate  (or  chlorate)  for  an  oxidizing  agent 
and  glue  (varnish).  The  P  is  kindling  for  the  S,  the  S  for 
the  wood  (hydrocarbon),  while  the  nitrate  furnishes  the  O 
for  rapid  combustion.  The  reactions  in  burning  a  match 
are: — 

P,  HhOfr  =   P205;         S  -f  O,  ==  SO,; 
Ha  +  O   -   H,0;         C  +  O,  =   CO.. 


BORON  AND  SILICON.  85 

<4  Safety  Matches  "  contain  no  P,  and  ignite  readily  only  when  the 
chemicals  of  the  match  are  rubbed  on  a  surface  of  red  phosphorus  (and 
powdered  glass  to  increase  friction). 

Phosphorus  glows  in  the  dark  (its  best  test).  Such  glowing  without 
heat  is  called  phosphorescence.  That  of  decaying  wood  and  of 
putrifying  fish  is  due  to  the  presence  of  P. 

EXP.  100. — Into  a  test  tube  half  full  of  water  drop  several  very  small 
pieces  of  P.  Cover  P  with  fine  crystals  of  K  Cl  O3  (oxidizing  agent). 
Allow  several  drops  of  concentrated  H2  S  O4  to  run  down  the  sides  of 
the  test  tube  upon  P.  The  P  burns  beneatli  the  water. 

A  combustible  element  burns  if  raised  to  the  igniting  point  in  pres- 
ence of  free  oxygen,  or  of  an  oxidizing  agent.  (In  this  case  C12  O4  from 
the  reaction). 


Calcium  Phosphate  (Ca3  2  P  Od)  forms  fully  one-half  by  weight 
of  bones,  and  is  the  source  of  P.  "Superphosphate  of  lime"  is  a  pecu- 
liar acid  phosphate  of  calcium  (Ca  H4  2  P  O4).  (See  ADDITIONAL 
EXPERIMENTS). 


CHAPTER   XXV. 


BORON    AND    SILICON. 

Boron  may  be  obtained  from  boron  oxide  B2  O3  as  a  brown  powder, 
and  also  in  yellowish-brown  crystals.  Boracic  acid  (H3  B  O3)  is  found 
in  the  lagoons  of  the  volcanic  regions  of  Tuscany.  Jets  of  stt  am  con- 
taining the  acid  issue  from  the  earth  and  are  absorbed  by  the  water. 
This  is  afterward  evaporated  by  heat  from  the  jets  leaving  the  crystal- 
lized acid.  Boracic  acid  is  also  made  from  borax. 

EXP.  101. — Upon  copper  (or  iron)  wire  covered  with  a  coating  of  the 
black  oxide,  melt  a  borax  bead.  The  melted  borax  dissolves  the  oxide 
leaving  the  bright  "  metallic  "  copper. 


Borax  (sodium  tetraborate,  Na2  B4  O7,  10  H2  O)  is  used 
in  welding  and  soldering  because  it  dissolves  the  oxide  of 
the  metal,  leaving  the  surfaces  bright.  (See  HARD  WATER.) 


86  CHEMICAL  PRIMER. 


EXP.  102.— Dissolve  borax  in  a  little  alcohol  (CZH5  H  O)  and  ignite. 
The  flame  has  a  peculiar  green  tint.  This  is  a  good  test  for  the  pres- 
ence of  a  borate. 

EXP.  103. — Dissolve  copper  oxide  in  borax  bead  in  oxidizing  flame  of 
the  blow-pipe.  Color  green  when  hot,  blue  when  cold.  Change  to 
reducing  flame,  color,  reddish-yellow.  Dissolve  in  like  manner  cobalt 
oxide,  bluish-black  in  oxidizing  flame,  intensely  blue  in  reducing  flame. 
Dissolve  Mn  O.2,  intense  reddish- violet  in  oxidizing  flame,  in  reducing 
flame,  almost  colorless. 

Borax  is  largely  used  in  blowpipe  analysis  as  a  "flux"  (see  larger 
text  books). 


Silicon  is,  next  to  O,  the  most  abundant  element,  though 
unlike  O,  it  is  always  found  combined  (not  free  or  native). 
The  larger  part  of  the  earth's  crust  is  silicon  oxide,  Si  O., 
(sand,  quartz),  or  silicates.  Many  precious  stones  (ame- 
thyst, agate,  etc.)  are  quartz  colored  with  some  metallic 
oxide.  Silicates  of  K  and  Na,  absorbed  by  roots,  give  the 
stiftness  and  shining  surface  to  corn  stalks  and  the  edge  of 
"sword  grass." 

Petrifaction  is  the  replacement  of  wood  by  stone  (silicates).  Cer- 
tain silicates  are  soluble  in  water  containing  alkaline  (K,  Na,  H3  N) 
carbonates.  As  fast  as  the  wood  placed  in  the  water  decays,  the  sili- 
cate is  deposited,  and  copies  very  precisely  the  lines  of  the  wood  (knots, 
grain,  etc.). 

Glass  is  a  mixture  of  several  silicates  (as  is  also  porcelain).  Common 
window  glass  (crown  or  plate  glass)  is  chiefly  calcium  and  sodium 
silicates.  Ca  hardens  and  gives  lustre.  Na  makes  fusible,  but  gives 
greenish  tint.  Bohemian  glass  is  chiefly  Ca  and  K  silicates,  K 
gives  no  color.  Flint  glass  is  chiefly  K  and  Pb  silicates.  This  can 
be  ground  into  imitation  gems,  prisms,  etc.  .  When  very  rich  in  lead 
it  is  known  as  "paste." 

EXP.  101. — Into  separate  pieces  of  soft  glass  fuse  Co  O,  Cu2  O, 
Mg  O  (from  EXP.  2),  Fe2  O3  (rust)  respectively,  the  pieces  are  colored 
blue,  ruby  red,  violet,  and  "  bottle  green. " 

(previously  moistened  by  drop  of  dilute  sulphuric  acid  to  liberate  boracic  acid.) 


ARSENICUM.  87 


Glass  is  colored  any  desired  tint  by  fusing  with  a  small  quantity  of 
some  metallic  oxide.  "Purple  of  Cassius"  (Exp.  115)  is  used  for  the 
finer  ruby  red ;  As2  O3  gives  the  white,  soft  enamel  of  lamp  shades, 
etc. 

Glass  is  annealed  by  bsiag  cooled  very  gradually  for  days.  When 
cooled  quickly,  it  is  very  brittle.  Lamp  chimneys  break  from  sudden 
change  of  temperature,  because  not  properly  annealed. 


CHAPTER  XXVI. 


ARSENICUM,  ANTIMONY,  AND  CHROMIUM. 

Arsenicum  (sp.  gr.  5.7)  is  a  brittle,  steel-gray  solid 
(semi-metal),  generally  found  in  combination.  Two  sul- 
phides, yellow,  As2  Sa  (arsenous  sulphide,  orpiment)  and 
red  As2  S2  (realgar),  occur  native. 

Caution. — Care  must  be  taken  in  experimenting  with  arsenicum,  as 
itself  and  its  compounds  are  violently  poisonous.  Use  very  small 
quantities  in  all  experiments,  especially  avoid  breathing  Ha  As  (see 
ANTIDOTES). 

EXP.  105. — Place  in  a  small  glass  tube,  drawn  out  and  closed  at  one 
end  "white  arsenic"  (As^  O3  arsenous  oxide  "ratsbane")  of  the 
bulk  of  a  pin's  head.  Heat  very  gradually;  the  "arsenic"  sublimes 
and  condenses  in  minute,  octahedral  crystals  in  the  upper  and  colder 
part  of  the  tube.  (Examine  crystals  with  a  lens).  Perform  the  same 
experiment,  placing  above  the  arsenous  oxide  (anhydride)  powdered 
charcoal  and  first  raising  the  charcoal  to  low  red  heat.  A  dark  mirror- 
like  ring  of  arsenicum  condenses  upon  the  tube  above,  and  a  garlic 
odor  is  distinctly  perceived. 

2As,03    +    C3    =    3CO2    +    As4 

EXP.  10(5. — Boil  a  few  decigrams  of  "  white  arsenic  "  in  water. 
As2O3    -f-    3H2O   =     2H3AsO7 

acid-formiu^  water  hydrogen 

oxide  or  arsenite 

anhydride  (acid) 

Filter  and  preserve  filtrate  as  a  sample  of  an  arsenite.  (Of  course 
this  may  be  considered  a  solution  of  arsenous  oxide  in  water.  See 
EXP.  10).  Place  a  centigram  of  As2  O3  in  ten  drops  of  H  N  O3,  and 


CHEMICAL  PRIMER. 


having  raised  to  the  boiling  point,  evaporate  over  water-bath  nearly  to 
drynes~.     Dilute  with  water,  filter  and  preserve  as  an  example  of  an 

arsenate. 

1.      As2O:i      -f      O2      =      As2O3 

arsenous  from  nitric  arsenic 

oxide.  acid,  an  oxide, 

oxidizing 
agent. 


2.       As2  O5    -f    3  H2  O     —     2  H3  As  O4 

anhydride.  water.  acid. 


KXP.  107. — To  copper  sulphate  solution  (5  per  cent.)  add  H,  N  H  O 
ti'l  the  precipitate  formed  is  partially  but  not  wholly  dissolved.  Filter, 
divide  filtrate  into  two  portions.  To  the  first  add  drop  by  drop  an 
arsemYe,  a  yree  i  precipitate  of  acid  copper  arsenite  (Cu  H  As  O3, 
"  Scheele's  Green,"  Paris  green,  etc.,  used  as  a  pigment)  falls.  To  the 
second  portion  add  a  few  drops  of  an  arsenal,  an  acid  copper  arsenate 
(H  Cu  AsO,)  light  blue  to  green,  falls. 

KXP.  108.-— To  silver  nitrate  solution  (2|  percent.)  add  H4N  HO 
and  proceed  as  in  EXP.  107.  From  first  portion  yellow  silver  arsenite 
(Ag3  AsO3)  falls  from  the  second  portion  a  beautiful  chocolate  silver 
arsenate  (Ag;}  As  O4)  falls. 

By  the  last  Exp.  an  arsenite  may  be  readily  distinguished  from  an 
.•irsenate.  The  pupil  may  learn  here  that  the  chemist  in  analysis 
depends  largely  upon  the  color  of  precipitates  as  well  as  upon  Solu- 
bility (or  insolubility)  in  various  reagents.  (See  EXP.  109  and  113). 
Arsenic  acid  is  used  in  preparing  aniUne  red  (for  dyeing)  and  other 
arseiiates  (especially  Na3  As  O4)  are  used  in  calico  printing. 

EXP.  109. — Into  a  flask  prepared  with 
safety-funnel  as  in  FIG.  32,  and  containing 
Zn,  pour  dilute  H2  S  O4  and  after  air  is 
expelled,  ignite  as  with  philosopher's  lamp. 
If  a  cold  porcelain  dish  is  held  in  the  flame 
moisture  alone  is  deposited.  Pour  through 
the  funnel  a  few  drops  of  arsenical  solution 
(ate  or  ite).  The  color  of  the  flame  changes 
and  the  cold  dish  is  smutted  with  arseni- 
cum.  (Just  as  a  candle-flame  smuts  a  cold 
dish  with  C).  Upon  the  mirror-like  spot 
place  a  drop  of  hot,  strong  nitric  acid,  it 
dissolves.  Upon  a  second  spot  place  a  drop 
of  calcium  chloride  ("bleaching  powder" 
answers),  it  dissolves.  (Unlike  the  anti- 
monial  spot.  See  EXP.  113). 


ARSENICUM.  89 


(1)— Zn     -{-     H2SO4     :    :     ZnSO,     -j-     H2 
(2)— H3    -f-    As     —     ^,As 

"nascent"  inflammable 

hydrogen  gas. 

(3)— 2  H,  As    +    O6     =    3  H,  O    -f    As,  O, 

from 
air. 

This  last  EXP.  is  Marsh's  test  for  "  arsenic  "  (any  compound  of 
arsenicum).  Of  course  in  all  tests,  the  chemist  must  first  make  sure 
that  his  materials  are  pure,  or  at  least  free  from  the  substance  he  is 
searching  for  in  the  unknown  liquid  or  material.  (See  MAGNESIUM)- 
If  a  cold  test-tube  be  placed  over  the  arsenical  flame,  octahedral  and 
characteristic  crystals  of  As2  O3  condense  upon  its  sides. 

EXP.  110. — Place  a  small  piece  of  clean  copper  wire  in  arsenical  solu- 
tion acidulated  with  hydrochloric  acid  and  boil.  (H  N  O3  must  not  be 
present).  Arsenicum  is  deposited  on  the  copper.  Wash,  carefully  dry 
and  heat  in  closed  glass  tube;  octahedral  crystals  of  A$2  O3  are 
deposited.  (Retifth's  test). 

EXP.  111.— Generate  hydrogen  by  heating  to  near  the  boiling  point 
a  strong  solution  of  Na  H  O  and  Zn. 

S 

Zn    -|-    SNaHO     =x=    Na*  Zn  O,,     -f    H2 

Add  a  few  drops  of  a  solution  of  "arsenic,"'  and  pass  gas  through 
wash-bottle  of  lead  acetate  solution  to  remove  traces  of  H2  S  ;  spread 
over  mouth  of  wash-bottle  filter  paper  moistened  with  Ag  N  O^. 

S 
H,     -f-    As     —     H:i  As 


H3  As  +  3H,  O  +  6  Ag  NO,  =  H3  A^O,  +  6  H  NO,  +  Agc 

The  free  silver  turns  the  paper  purplish-black.  (Fleitmann's  test 
distinguishes  arsenicum  in  presence  of  antimony). 

Arsenicum  (and  its  compounds)  is  a  powerful  antisep- 
tic. Bodies  of  those  poisoned  with  it  are  sometimes  pre- 
served from  putrefaction  for  years.  In  small  doses  it 
stimulates  and  causes  persons  to  grow  fat.  In  a  certain 
district  of  Hungary  the  peasants  habitually  eat  "arsenic/' 
It  is  said  to  beautify  the  complexion,  but  its  use  is  a  very 


90  CHEMICAL  PRIMER. 

dangerous  practice.     All  the  symptoms  of  arsenical  poison- 
ing appear,  if  one  ceases  the  practice. 


Antimony  (sp.  gr.  6.7)  is  a  brittle,  highly  crystalline 
solid  (semi-metal),  with  brilliant  lustre.  Upon  the  surface 
of  its  bluish-white  masses  are  usually  fern-like  crystalliza- 
tions. 

EXP.  112. — Into  an  acidulated  (H  Cl)  solution  of  antimony  (tartar 
emetic,    K  Sb  O   C4H4O6)   potassium    "antimonyl "    tartrate)    pas» 
H2  S  gas  (or  its    solution).     Sb2  S3,  antimonous  sulphide,  falls.     Fil- 
ter, dry,  and  heat  carefully;  it  turns  greyish-black. 

Native  antimonous  sulphide  (gray  antimony,  or  antimony  glance) 
is  the  source  of  the  Sb  of  commerce. 

EXP,  113.— Perform  experiment  109,  using  antimonial  solution, 
instead  of  arsenical.  Dark  antimony  spots  are  obtained.  Upon  one, 
place  solution  of  calcium  chloride,  it  is  unaffected;  upon  another,  place 
a  drop  of  hot  nitric  acid,  it  is  oxidized  (turned  white,  Sb2  O3),  but  not 
dissolved. 

Antimony  is  a  constituent  of  several  important  alloys, 
as  type  metal,  etc.  (see  ALLOYS). 

An  alloy  is  a  mechanical  mixture  of  two  or  more 
metals  (including  semi-metals).  If  one  of  the  metals  is 
mercury,  the  alloy  is  called  an  amalgam.  A  mechanical 
mixture  differs  from  a  chemical  compound  in  that  it  may 
contain  its  constituents  in  any  proportions,  but  a  chemical 
compound  must  contain  each  constituent  in  some  one  pro- 
portion, or  multiple  of  that  proportion. 


Chromium  (sp.  gr.  4.8)  is  a  silver- white  metal  (considered  a  metal, 
though  ordinarily  negative  to  H).  (Let  the  student  learn  right  here, 
that  the  order  of  elements  in  Table  No.  1  is  the  usual  order.  Rarely 
an  element  takes  a  different  position  when  obtained  by  electrolysis 
under  different  circumstances,  or  from  different  compounds). 


GOLD  AND  PLATINUM.  91 

Chromium  makes  both  acid-forming  (Cr  O3)  and  basic  (Cr2  O3)  oxides 
with  corresponding  acid  (H2  Cr  O4  chromic  acid)  and  base 
(Cr.2  6  H  O)  respectively. 

The  principal  ore  of  chromium  is  "  chromic  iron  ore"  (FeCr2OJ. 
A  few  of  its  compounds  are  extensively  used  in  the  arts,  viz. :  potas- 
sium chroinate  (K2CrO4)  potassium  bichromate  (di-)  (K2  Cr2  O7)  and 
lead  ehromate  (Pb  Cr  O4)  "chrome  yellow"  (see  ANA.  CHARTS). 


CHAPTER  XXVII. 


G-OLD    AND    PLATINUM. 

NOTE. — With  this  chapter  we  begin  the  study  of  the  metals  proper. 
In  general,  a  metal  is  an  elementary  substance  (1)  with  a  peculiar 
lustre,  called  metallic,  (2)  insoluble  in  water,  (3)  a  good  conductor  of 
heat  and  electricity,  (4)  positive,  with  reference  to  hydrogen,  and  (5) 
uniting  with  H  and  O  to  form  bases.  Chemists  are  not,  however, 
agreed,  as  to  any  precise  definition,  and  the  line  between  metals  and 
non-metals  cannot  be  sharply  drawn.  This  is  the  case  with  terms  used 
in  all  sciences  (except  in  the  exact  sciences,  included  in  the  general 
term  mathematics).  No  line  can  be  drawn  between  soluble  and  insol- 
uble substances,  for  one  kind  fades  gradually  into  the  other.  (Though 
Pb  is  considered  insoluble,  traces  of  the  metal  may  be  found  in 
distilled  water,  that  has  been  in  a  leaden  dish  for  a  day  or  two).  So  in 
physics,  no  line  can  be  definitely  drawn  between  "hot"  substances  and 
"cold"  ones,  but  the  terms  are  relative. 

For  uses  .of  the  metals,  reduction  of  their  ores,  etc.,  see  fuller 
accounts  in  the  cyclopaedia  and  in  larger  works  on  chemistry. 

Gold  (sp.  gr.  19.3,  fusing  point  1100°)  is  found  native 
(free),  frequently  alloyed  with  silver,  in  quartz  veins,  allu- 
vial (by  water)  deposits,  ("placers")  etc.  It  is  obtained  by 
(I)  quartz  mining,  (2)  placer  mining,  and  (3)  hydraulic 
mining. 


92  CHEMICAL  PRIMER. 

EXP.  114.—  Dissolve  apiece  of  gold  leaf  in  globule  of  Hg.  Place 
the  amalgam  on  hard  glass  and  in  window  with  outward  draft;  keep 
at  dull  red  heat  for  a  little  time.  Hg  distills  leaving  the  gold. 

Mercury  is  used  to  extract  gold  from  the  sands  or  from 
pulverized  quartz.  The  amalgam  of  Au  and  Hg  is  then 
submitted  to  pressure  in  "  bags,"  which  squeezes  out  much 
of  the  Hg.  The  remainder  is  driven  off  by  distillation, 
but  the  Hg  is  saved,  not  thrown  away  as  in  the  experi- 
ment. 

Gold  is  a  very  brilliant  orange-yellow  solid,  the  most 
ductile  and  malleable  of  the  metals  (280,000  sheets  of  the 
finest  gold-leaf  make  only  one  inch  in  thickness).  It  was 
known  as  the  "  king  of  metals,"  and  together  with  plat- 
inum and  silver  (also  rare  metals  of  platinum  group)  is 
called  a  noble  metal.  The  others  in  contrast  are  called 
base  metals.  It  is  insoluble  hi  any  of  the  common  acids, 
but  dissolves  in  "aqua  regia,"  chlorine-  water  or  bromine- 
water. 

Pure  gold  is  too  soft  for  jewelry,  coin,  etc  ,  and  is  hardened  by  cop- 
per. A  carat  is  ^.  An  alloy  containing  ||  pure  gold  is  said  to  be 
gold  of  16  carats  fine. 

When  gold  is  dissolved  in  aqua  regia  (Exr.  44),  a  solution  of  auric 
chloride  (Au  Cla)  is  formed.  (Evaporate  to  dryness  over  water  bath, 
dilute,  filter,  and  preserve  filtrate  as  a  solution  of  gold  chloride). 
Vliroiis  cyanide  (Au  C  N)  dissolved  in  solution  of  KCN  is  used  in 
electro-gilding. 

EXP.  115.—  (1)  To  a  solution  of  an  auric  salt  (Au  C13)  add  H,  S.  A 
brown  precipitate  of  Au,  S;  falls,  soluble  in  (H4N).2S. 

2AuCl3    +    3H,S    -    Au.2S,    -f    6  H  Cl 

(2)  —  To  solution  of  salt  of  gold  (Au  C13)  add  ferrous  sulphate. 


2AuCl      -|-    6FeSO4     =    Au2    -}-    Fe2  C16    -j- 

ferrous  free  ferru-  ferric 

sulphate  gold  chloride  sulphate 

Boil  precipitate  in  H  Cl,  mix  with  e^ual  bulk  of  borax  and  fuse  in 
strong  blowpipe  flame.     A   "button  "  of  pure  gold  is  obtained. 


GOLD  AND  PLATINUM.  93 

(3) — Add  a  few  drops  of  solution  of  stannous  and  stannic  chlorides 
(Cl  water  put  into  Sn  Cl.^  gives  Sn  C14)  to  dilute  solution  of  Au  C13, 
a  purplish  finely-divided  precipitate,  "purple  of  Cassius,"  (composition 
doubtful)  falls.  The  same  precipitate  is  slowly  obtained,  if  tin  foil  is 
placed  in  solution  of  Au  C13. 


Platinum  (sp.  gr.  21.5,  fus.  pt.  2000°)  is  found  native 
usually  alloyed  ("platinum  ore")  with  iron,  copper,  or  some 
of  the  rare  metals  (palladium  used  to  color  "salmon" 
bronze  ,  rhodium,  iridium  used  to  tip  gold  pens,  ruth- 
enium and  osmiuin)  of  the  platinum  group.  Like  gold, 
it  is  insoluble  in  any  one  of  the  common  acids,  but  dis- 
solves in  chlorine-water,  and  slowly  in  aqua  regia,  (H  Cl 
+  H  N  O3).  Its  "ore"  is  worked  by  means  of  the  oxy-hy- 
drogen  blowpipe,  coal  gas  being  usually  used  in  place  of 
H. 

Platinum  is  to  the  chemist  an  exceedingly  useful  metal.  From  it 
he  makes  crucibles,  stills  (see  H2  S  O4),  wire,  blowpipe  tips,  etc. 

Platinum  sponge  and  platinum  black  (finely  divided  IJ)  have  the 
power  of  absorbing  O  and  thus  oxidizing  easily  oxidizible  substances 
(ether,  alcohol,  hydrogen,  etc.)  brought  in  contact  with  it.  (See 
ADD.  EXP.) 


94  CHEMICAL  PRIMER. 


CHAPTER    XXVIII. 


SILVER,    MERCURY    AND    LEAD. 

Silver  (sp.  gr.  10.5,  fus.  pt.  1040°)  is  found  native  often 
alloyed  with  copper,  mercury  and  gold.  Ag.2  S  (mixed 
with  other  sulphides  as  galena,  Pb  8)  and  Ag  01  ("horn 
silver")  are  among  its  chief  ores. 

EXP.  116. — Repeat  EXP.  5,  and  place  the  resulting  Ag-Cl,  mixed 
with  a  little  K ,  C  O ,  (or  Na2  C  O3)  upon  charcoal  and  heat  in  reducing 
flame  of  the  blowpipe.  A  silver  globule  ("button")  is  obtained. 

(1)— K2CO,    +    2AgCl    =    Ag2CO3    +    2KC1 
(2)— Ag2CO3    =    Ag20    -f    C02 


(3)-2Ag20    -{-    C    =    Ag4 

deoxidizing 
agent. 


co< 


The  melted  globule  absorbs  oxygen  from  the  air,  and  if  cooled  quickly 
the  escaping  O  breaks  the  hardening  surface,  and  the  melted 
("molten")  silver  runs  out  ("spitting"  or  "sprouting"). 

Silver  is  a  brilliant  white  metal.  For  jewelry,  coin, 
etc.,  it  is  hardened  with  Cu.  It  is  used  for  silvering  mir- 
rors because  it  takes  a  high  polish.  It  is  not  acted  upon 
by  fused  caustic  alkalies  (K  HO,  Na  HO,  etc.),  as  glass 
and  platinum  are,  and  hence  certain  chemical  vessels  are 
made  from  the  metal.  It  expands  at  the  moment  of  solid- 
ification and  hence  can  be  cast  (copies  fine  lines  of  the 
mould). 


SILVER,  MERCURY  AND  LEAD  95 

Silver  i»  obtained  from  the  sulphide  by  (1)  roasting  the  pulverized 
ore  with  salt,  Ag,  S  -f-  2  Na  Cl  =  2  Ag  Cl  -f-  Na,  S,  and  (2)  by 
placing  the  Ag  Cl  in  a  cylinder  with  H.2  O,  Hg  and  Fe  scraps, 
2  Ag  Cl  -f-  Fe  =  Fe  C12  -}-  Ag2.  The  Hg  forms  an  amalgam 
with  silver  from  which  the  Ag  is  obtained,  as  gold  is  obtained  from 
gold  amalgam.  The  process  of  EXP.  116  is  too  expensive  for  the  prac- 
tical miner,  though  used  by  the  assay er. 

Silver  may  be  freed  from  lead  by  fusing  the  alloy,  and  as  Pb  crys 
tallizes  first  it  may  be  skimmed  out.  This  leaves  a  portion  of  the  Pb 
which  may  be  completely  extracted  by  cupclhltion.  (A  cupel  is  a 
shallow  dish  made  of  bone  ashes).  The  Ag  containing  Pb  and  other 
impurities  is  placed  in  the  cupel  and  raised  to  the  red  heat.  A  hot  cur- 
rent of  air  plays  upon  the  fused  mass.  The  Pb  is  oxidized  and  the 
Pb  O  is  absorbed  by  the  cupel.  After  a  while  the  refiner  sees  the 
mirror-like  globule  of  pure  silver  and  quickly  removes  it  lest  it  also 
oxidize  and  waste. 

The  most  important  salt  of  silver  is  the  nitrate  (Ag  N  O3,  lunar 
caustic).  It  forms  with  organic  compounds  by  the  action  of  light  a 
very  stable,  dark  compound,  and  hence  is  used  in  indelible  inks  (see 
EXP.  89). 

The  changes  which  the  salts  of  silver  undergo  when  exposed  to  light, 
especially  in  presence  of  organic  matter,  is  the  basis  of  photography 
(see  EXP.  5,  NOTE). 

EXP.  117. — Borrow  an  old  "negative"  from  a  photographer,  and 
upon  a  sheet  of  prepared  paper  (moistened  with  silver  salt  and  dried  in 
the  dark)  furnished  by  him,  print  by  means  of  a  few  moments  exposure 
to  direct  sunlight  a  photograph.  After  a  few  hours  exposure  (even  to 
reflected  light),  the  picture  fades  out,  because  the  entire  paper  turns 
black.  [The  photographer  applies  reagents  to  dissolve  from  the 
unblackened  portion  the  silver  salt,  and  thus  preserves  the  picture.  In 
preparing  the  negative  he  first  covers  the  glass  with  an  organic  film 
(collodion)  to  receive  the  silver  salts.  (Hold  a  lens  up  between  the 
window  and  a  sheet  of  paper.  The  lens  converges  the  rays  of  light  and 
forms  an  inverted  image  of  the  window  upon  the  paper.  This  explains 
the  formation  of  the  "negative  "  in  the  "camera").  After  the  forma- 
tion of  the  image,  he  treats  the  slide  (glass)  with  reagents  whose  action 
upon  the  part  previously  influenced  by  the  light  is  different  from  their 
action  upon  the  part  uninfluenced  by  the  light]. 

A  solution  of  Ag  C  N  in  solution  of  K  C  N  is  used  in  electroplating. 


96  CHEMICAL   PRIMER. 

Mercury  or  "quicksilver"  (sp.  gr.  13.5,  f us.  pt.,  i.  e., 
freezing  poiat — 39.4°)  is  found  native  in  small  quantities, 
.but  its  chief  source  is  the  ore  cinnabar  (Hg  S  mercuric 
sulphide)  from  which  the  liquid  metal  is  obtained  by  mix- 
ing with  iron  turnings  (or  lime)  and  distilling. 

HgS    -f-    Fe    =    FeS    -f-    Hg 

When  Hg  S  is  prepared  artificially  (by  subliming  together  S  and 
Hg)  it  is  called  vermilion  and  is  used  as  a  pigment. 

Mercury  is  largely  used  in  making  thermometers,  barometers,  etc., 
for  collecting  gases  soluble  in  water  (see  FIG.  29),  for  extracting  gold 
and  silver  from  their  ores,  for  silvering  mirrors  (tin  amalgam),  and 
formerly  was  much  used  in  medicine.  "Blue pill"  is  Hg  "rubbed 
up  "  \*  ith  lard  till  the  globules  are  not  visible  to  the  naked  eye. 

EXP  118. — Pour  a  little  dilute  nitric  acid  upon  a  considerable  quan- 
tity of  Hg,  and  bringing  to  boiling  point,  leave  over  night;  pour  off 
from  the  excess  of  Hg  and  preserve  as  solution  of  mercuro?^  nitrate 
(Hg-2  2  N  O3).  Dissolve  a  small  globule  of  Hg  completely  in  an  excess 
of  hot,  strong  nitric  acid.  Evaporate  nearly  to  dryness,  dilute  and 
preserve  as  solution  of  mercuric  nitrate  (Hg  2  N  O3).  (Of  course 
these  salts  may  be  obtained  dry  by  evaporation  over  a  water  bath). 

EXP.  119. — To  a  solution  of  mercurous  nitrate  add  H  Cl.  • 

1^  2  NO      -f    2HC1    =    Hg.CI,    -f    2HNO3 

white 
precipitate 

Mercurous  chloride  (calomel,  Hg2  C12)  is  an  insoluble, 
(in  water)  white  powder.  It  acts  powerfully  upon  the 
glandular  system  (liver,  etc.),  and  in  large  or  long  con- 
tinued doses  produces  salivation  (excessive  action  of  the 
salivary  glands)  and  other  serious  results.  It  was  formerly 
much  used  in  medicine,  by  some  almost  as  a  "cure  all." 

EXP.  120. — To  a  solution  of  mercuric  nitrate  add  H  Cl. 

Hg2NO3    +    2HC1    =    HgCl2    -f    2HNO3 

There  is  no  precipitate  because  Hg  C12  is  soluble.  Place  a  drop  of 
the  solution  on  glass  and  evaporate  at  low  Iwit.  White  crystals  of 
Hg  Cla  are  obtained. 


XLLVKR,  MERCURY  AND  LEAD.  97 

Mercuric  chloride  (HgCl,  corrosive  sublimate)  is  a 

powerful  poison  and  a  strong  antiseptic.  It  is  used  to 
prevent  the  decay  of  wood  and  its  dilute  solution  in  alco- 
hol brushed  over  specimens  in  Natural  History  preserves 
them  (see  ANTIDOTES). 

EXP.  121. — In  a  solution  of  salt  of  Hg  place  a  clean  (by  H  N  O;. 
and  afterward  H2  O)  copper  wire.  It  is  soon  coated  with  a  mirror  of 
Hg,  more  apparent  if  dried  by  blotting  paper  and  gently  burnished 
with  soft  cloth.  An  equivalent  amount  of  copper  passes  into  the  solu- 
tion to  take  the  place  of  the  displaced  Hg.  Cut  off  the  mirrored  end 
of  the  wire,  and,  placing  in  closed  glass  tube,  heat.  Hg  distills  and 
globules  of  the  metal  gather  upon  the  sides  of  the  tube. 

In  almost  any  solution  containing  soluble  compound  of  Hg,  it  may 
be  detected  by  this  test.  No  test  for  Hg  should  be  considered  com- 
plete, unless  metallic  globules  are  obtained.  A  lens  will  often  reveal 
the  globules,  if  the  amount  of  mercury  is  exceedingly  small. 

EXP.  122. — To  mercurows  nitrate  add  K  I,  green  mercurows  iodide 
(Hg.2 I.2)  falls.  To  mercun'c  nitrate  add  K  I,  red  mercuric  iodide 
(Hg  I2)  falls  (Exp.  9).  Wash,  dry,  place  in  cold  tube,  and  sublime. 
Hg  I2  condenses  on  the  sides  of  the  tube  in  yellow  crystals;  rub  crys- 
tals with  stick,  they  change  to  the  original  red.  This  change  of  color 
may  be  repeated  indefinitely. 

NOTE. — It  will  be  noticed  that  Hg  forms  two  classes  of  salts,  i<- 
(Hg  —  dyad),  and  ous  (Hg.2  =:  dyad).  The  same  is  true  of  Cu.  Iron 
in  ous  salts  makes  Fe  =•  dyad,  in  ic  salts  Fe2  —  hexad.  Aluminum 
forms  but  one  class  of  salts,  but  all  molecules  of  aluminum  compounds 
contain  at  least  two  atoms  of  Al,  and  A12  —  hexad  (see  REF.  TABLE, 
No.  1). 

Lead  (sp.  gr.  11.4,  fus.  pt.  334°)  is  rarely  found  free. 
Its  chief  ore  is  lead  sulphide  (Pb  S,  galena),  often  carrying 
Ag2S.  The  roasting  ("smelting")  of  this  ore  and  separa- 
tion of  the  metal  is  a  very  simple  process.  Pb  is  soft  and 
malleable,  and  when  fresh  cut  has  a  lustrous  bluish-gray 
color,  quickly  dulled  by  oxidation.  Its  common  uses  are 
well  known  to  every  school  boy.  It  contracts  in  solidi- 
fying, and  hence  cannot  be  cast  (i.  e.  to  copy  the  fine  lines 
of  the  mould). 


CHEMICAL  PRIME  It. 


EXP.  123. — Make  two  moulds  by  boring  conical  cavities  into  plaster 
of  Paris  (CaSO4,  2  H2  O)  and  making  fine,  clean-cut  grooves  on  the 
sides.  Into  one  pour  melted  lead.  Into  the  other  pour  melted  lead, 
in  which  a  little  Sb  and  Sn  has  been  previously  dissolved  (type 
metal).  The  first  casting  is  blunt  and  does  not  copy  the  grooves ;  the 
second  is  sharp,  pointed,  and  copies  the  grooves  accurately.  This  is 
caused  by  expansion  of  the  crystalline  Sb  and  Sn  in  solidifying. 

Water  used  for  drinking  purposes  should  not  be  brought 
great  distances  in  lead  pipes  (unless  the  water  contains 
considerable  quantities  of  carbonates  or  sulphates,  which 
coat  the  lead  with  white  coat),  and  water  that  has  stood 
over  night  in  the  short  lead  pipe  connecting  with  faucet 
should  be  allowed  to  run  out  before  drinking.  Water  con- 
taining even  minute  quantities  (and  otherwise  practically 
harmless)  of  ammoniacal  salts  (from  decomposition  of 
organic  matter)  dissolves  lead  and  keeps  the  surface  bright. 
Chronic  lead  poisoning  is  produced  by  drinking  such 
water.  Lead  is  an  ''accumulative"  poison,  i.  e.,  it  remains 
in  the  system  and  is  thrown  off  with  difficulty.  Painters 
are  often  attacked  by  "  colic  "  produced  by  lead  poisoning. 

Fruit  cans  should  not  be  soldered  with  an  alloy  of  Pb  (See  EXP.  127 
and  connection).  Metallic  Pb  is  .not  poisonous  (Plumbers  are  not 
attacked  by  "lead  colic  "). 

Litharge  (Pb  O)  (see  EXP.  50),  "  red  lead"  (Pb3  O4)  "  sugar  of 
lead  ""(lead  acetate  Pb  2  C2  H3  O2)  and  "white  lead"  (chiefly 
Pb  CO3)  used  in  painting,  are  important  compounds.  All  are  poisonous, 
especially  the  very  soluble  acetate  (See  ANTIDOTES,  ALSO  EXP.  11). 

White  lead  is  made  as  represented  in 
Fig.  33.  A  roll  of  lead  (B)  is  placed  in  an 
earthen  vessel,  and  below,  weak  vinegar  (A). 
Above  (and  around)  is  packed  decaying  tan 
bark  (C)  and  refuse.  These  vessels  are 
arranged  in  immense  piles,  the  heat  of  the 
decomposition  assists  the  evaporation  of 
the  vinegar  and  in  five  or  six  weeks  the 
lead  is  all  converted  into  Pb  C  O3 


Fiff.   33. 


Cu,  Fe,  Zn,  and  Sn.  99 


Pb    -f    O    -f-    HC2H302    =    PbHOC,H3O2 

from  from  basic  salt 

air  vinegar 

CO2    -f-    PbHOC2H3O2    —    PbCOtt    4-    HC2H3O.2 

from  decomposing  basic  lead  -'white  unites  with 

refuse  acetate  lead"  another  portion 

of  Pb 

White  lead  is  largely  adulterated  with  gypsum  (CaSO42H.,  O; 

heavy  spar  (Ba  S  O4)  etc.     (Pure  Pb  C  O3  dissolves  completely  in  hot 
dilute  HNO3) 

EXP.  124. — Add  a  little  mucilage  to  lead  acetate  solution  (sympathetic 
ink)  and  write  with  fine  hand  a  few  words.  Dry;  they  are  invisible. 
Moisten  the  paper  and  allow  H2S  gas  to  come  in  contact  with  it.  The 
letters  become  black  (see  EXP.  8). 

H2  S  is  a  test  for  lead  and  vice  versa  lead  acetate  (paper  moistened 
with  it)  is  a  test  for  H2S.  "A  body  acted  upon  characteristically  Inj  a 
reagent  is  as  good  a  test  for  the  reagent,  as  the  reagent  is  for  it." — AUJield. 
(see  test  in  ANA.  CHARTS). 


CHAPTER  XXIX 


Cu,    Fe,    Zn,    and    Sn. 

Copper  is  found  free  in  large  masses  (Lake  Superior 
mines).  Its  most  common  ore  is  copper  pyrites  (Cu  S? 
and  Fe  S  mixed),  from  which  it  is  obtained  by  roasting 
with  a  silicate  to  remove  the  iron  as  iron  silicate,  and  again 
roasting  the  Cu  S.  It  is  a  reddish  metal,  highly  malleable 
and  ductile.  With  the  exception  of  Ag  it  is  the  best  con- 
ductor of  heat  and  electricity.  Brass,  bronze,  and  bell-metal 
contain  Cu  (see  ALLOYS). 

The  salts  of  copper  are  poisonous  (see  ANTIDOTES). 
Substances  containing  acids  (fruits,  jellies,  pickles,  etc.) 
should  never  be  put  in  copper  (or  brass)  utensils.  Fats 


100  CHEMICAL  PRIMEIL 

dissolve  copper  oxide,  and  therefore  should  be  put  into 
copper  dishes  only  when  the  vessels  are  bright.  Copper 
sulphate  ("blue  vitrol,"  "blue  stone"  Cu  S  O4  5  ELO)  is 
used  in^dyeing,  calico  printing  and  in  galvanic  batteries  (see 
EXP.  34).  The  native  malachite  (Cu  C  O3  -f  Cu  2  H  O) 
takes  a  high  polish  and  is  used  for  jewelry  and  other  orna- 
mental articles.  Verdigris  is  copper  acetate  (Cu  2  C2  H3  O2) 
though  the  name  is  often  applied  to  the  artificial  carbonate. 

EXP.  125.  —  Into  solution  of  a  copper  salt  (as  Cu  S  O4)  put  a  piece  of 
clean  iron.  It  is  coated  with  copper,  an  equivalent  amount  of  iron 
passing  into  solution. 

CuSO4    -}-     Fe     =     FeSO4     -f-     Cu  (deposited  on  iron). 

EXP.  126.  —  AddH4NHO  to  cupric  solution,  a  characteristic  blue 
precipitate  soluble  in  excess  of  H4  N  H  O  is  obtained. 


-f    2H.NHO     =2H4N    NO3    -f    Cu2HO 

(See  NOTE  EXP.  122.) 


Iron  (sp.  gr.  7.8,  fus.  pt.  1000°  to  1800°)  is  the  most 
important  of  all  the  metals.  It  is  rarely  found  free  (always 
in  aerolites)  but  hi  combination  it  is  widely  distributed, 
traces  being  found  in  the  blood  of. animals  and  in  the 
juices  of  plants.  It  is  a  soft,  silver- white  metal  (if  pure). 
Among  the  most  important  of  its  numerous  ores  are  Fe2  O3 
("specular  iron,"  hematite),  Fe.2  6  H  O  +  Fe2  O3  (brown 
hematite,  limonite,  Fe3  O4  ("  magnetic  iron")  and  Fe  C  O3 
(spathic  iron,  ferrous  carbonate).  The  value  of  the  ore 
depends  as  much  upon  the  nature  of  its  impurities  as  upon 
the  percentage  of  iron. 

The  old  process  of  reduction  ("Direct  Process")  was  to  roast  the 
ore  with  charcoal  in  an  open  "forge"  fire.  The  pasty  mass  of  reduced 
iron,  called  "bloom,"  separates  from  the  fused  silicates  (or  fused  glass), 
called  "slag." 

The  modern  process  ("'Indirect  ")  consists  of  two  parts,  (1)  obtaining 


Cu,  Fe,  Zn,  and  Sn. 


101 


the  reduced  iron  from  the  ore,  not  pure,  but  containing  a  large  percent- 
age of  C.  (This  is  cast  iron,  or  "pig  iron.").  (2)  The  production 
of  iron  nearly  free  from  C  ("wrought  iron")  from  the  cast  iron. 

1.  The  ore  is  placed  in  a  "blast  furnace  "  with  layers  of  coal,  coke, 
and  "flux,"    [the  last,  limestone  Ca  CO3,  if  impurities  are  silicates 
(clayey),  and  silicates,  if  the  impurities  are  calcareous.     Of  course,  the 
object  is  to  form  a  "slag"  of  calcium  glass.]     Hot  air  is  driven  in 
below.     The  heat  of  the  furnace  is  intense  and  its  action  continuous. 
The  "life"  of  the  furnace  fire  is  often  twenty  years,  fresh   material 
being  ceaselessly  supplied  from  above.     The  melted  iron  and  "slag" 
(floating  on  iron)   is  drawn  off  below.     [The  hot  C  O2  (and  unburnt 
gases),  passing  from  chimney,  are  utilized  for  heating  the  air  driven  in 
below].     The  iron  runs  into  a  large  main,  called  "sow,"  and  thei^ce 
into  lateral  moulds  called  "pigs"  (hence  "pig  iron"). 

2.  Pig  iron  (2  to  5  per  cent,  of  C)  is  changed  to  wrought  iron  (less 
than  ^  per  cent,  of  C)  by  burning  out  the  C  (also  S;  Si  andP)  in  a  rever- 
beratory  furnace,  "  puddling  furnace  "  (Fig.  34).     Fuel  burns  upon  the 
grate  A,  pig  iron  is  placed  upon  the  floor  B,  and  is  frequently  stirred 
by  means  of  openings  in  the  side. 


Fig.  34. 

Steel  contains  more  C  than  wrought  iron  and  loss  than 
cast  iron.  It  may  be  made  by  heating  bars  of  wrought 
iron  to  redness  in  contact  with  powdered  charcoal  for  eight 
or  ten  days.  This  is  called  the  cementation  process. 

Bessemer  steel  is  made  by  decarbonizing  the  best    pig 


102  CHEMICAL  PltlMER. 

iron  at  a  fearful  heat  in  an  egg-shaped  vessel  ("converter") 
lined  with  infusible  material.  Hot  air  is  driven  in  below 
through  numerous  openings  by  means  of  a  powerful  engine. 
P,  Si  and  S  are  also  removed.  "Looking-glass  "  iron  con- 
taining a  known  quantity  of  C  and  a  little  Mg  is  then 
added.  Bessemer's  process  is  a  rapid  one.  Bessemer's 
steel  is  largely  used  in  constructing  railroads,  bridges,  etc. 
Steel  expands  at  the  moment  of  solidification  and  therefore 
can  be  cast.  Few  metals  besides  iron  can  be  welded.  (To 
be  welded  a  metal  must  soften  before  melting.  Cast-iron 
cannot  be  welded).  Iron  (or  its  salts)  is  largely  used  in 
medicine  as  a  tonic. 

Ferrous  sulphate  (FeSO4,  7H2O,  green  vitriol,  copperas)  is  used 
in  dyeing,  making  ink,  etc.  Fe  S  is  used  in  preparing  the  reagent 
H.2S  (Exp.  7).  Iron  disulphide  (FeS2,  iron  pyrites,  fool's  gold) 
may  be  readily  distinguished  from  gold  by  heating  and  observing  the 
odor  of  SO.2. 


Zinc  (sp.  gr.  6.9,  fus.  pt.  410°)  very  rarely  occurs  native. 
Its  chief  ores  are  Zn  C  O3  (smithsonite),  Zn  S  (Zinc  blende) 
and  Zn  O  ("red  zinc  ore"  colored  red  by  an  oxide  of  Mn).  It 
is  bluish-white  crystalline  metal.  Fe  dipped  in  melted  Zn 
is  coated  with  the  metal  and  forms  what  is  improperly 
termed  galvanized  iron.  Water  that  has  stood  a  long 
time  in  zinc-lined  vessels  (tanks)  is  unfit  to  drink.  Zn  O 
(zinc  white)  is  used  as  a  pigment.  (See  ALLOYS). 


Tin  (sp.  gr.  7.3,  fus.  pt.  230°)  is  obtained  from  its  prin- 
cipal ore  Sn  Oa  (tin  binoxide,  stannic  oxide,  "tin  stone  ") 
by  roasting  with  carbon  in  reverberatory  furnace.  It  is  a 
lustrous,  white,  highly  crystalline  metal,  malleable  and 
ductile.  When  a  bar  of  tin  is  bent,  a  crackling  sound. 


Hi,  Co,  Ni,  Mn,  Al,  and  Mg.  103 

("tin  cry")  caused  by  the  friction  among  the  crystals,  is 
heard. 

"Tin  ware  "  is  really  iron  ware  coated  with  Sn  (dipped 
in  the  melted  metal).  When  the  tin  wears  off',  the  iron 
rust  (Fe2  O3,  or  hydrated  Fe2  6  H  O)  is  seen.  Tin  is  often 
adulterated  with  (the  cheaper)  lead.  Fruit,  contained  in 
cans  coated  with' such  "tin"  is  unfit  to  eat,  for  it  contains 
poisonous  lead  salts.  Pb  is  easily  detected  by 

EXP.  127. — Upon  a  piece  of  tinned  iron  ("tin")  place  a  drop  of 
H  N  O,j  and  evaporate  to  dryness.  Add  a  drop  of  K  I  solution,  yellow 
Pb  I,  is  formed,  if  lead  is  present. 

PbSNO,    -f     SKI     —     2KNO3    +    Pbl, 

yellow 

Fins  made  of  brass  'wire,  copper  utensils,  iron  tacks,  etc. ,  are  covered 
with  a  thin  coat  of  tin  to  give  bright  surface.  Tin  is  largely  used  in 
making  alloys  (which  see). 

Tin  bisulphide  (SnS2)  a  bright  golden-yellow,  is  known  as  mosaic 
gold,  and  is  used  in  decorative  painting.  Sn  C12  (stannous  chloride) 
and  Sn  C14  (ic)  are  largely  used  in  dyeing. 


CHAPTER  XXX. 


Bi.    Co,   Ni,   Mn,  Al,   and    Mg. 

Bismuth  (sp.  gr.  9.8,  fus.  pt.  264°)  is  a  brittle,  purplish- 
white,  crystalline  metal.  It  forms  alloys  with  other  met- 
als, expanding  much  in  solidifying  and  remarkable  fen- 
their  low  melting  point. 

EXP.  128.— Fuse  Bi  (5  dcg.),  Pb  (3  dcg.)  and  Sn  (2  dcg.)  together. 
The  alloy  is  fusible  metal  (one  variety).  Place  the  cold  globule  in 
water  and  raise  to  the  boiling  point.  Notice  that  the  alloy  melts  (at 
91.6°)  before  the  water  boils. 


104  CHEMICAL  PRIMER. 


Fusible  metal  is  used  for  taking  casts  of  wood  cuts,  etc.  Fusible 
metal  (of  different  composition  and  melting  at  some  definite  point  above 
100°),  is  used  for  "  safety  plugs  "  in  steam  engines.  When  the  tem- 
perature approaches  a  point  that  would  be  dangerous,  the  plugs  melt 
and  let  the  steam  escape. 


Cobalt  (sp.  gr.  18.6)  is  a  silver  white  metal.  Its  salts  (acetate,  sul- 
phate, nitrate,  chloride),  are  used  for  sympathetic  ink  (see  clyclopaedia). 

Exr.  129. — Divide  a  solution  of  cobalt  chloride  into  two  parts. 
Thicken  each  with  a  little  pure  mucilage.  To  one  add  a  few  drops  of 
a  salt  of  nickel.  Write  with  a  fine  pen  upon  slightly  pinkish  papers. 
The  writing  is  invisible.  Heat  each  paper  upon  metallic  support.  The 
ink  containing  nickel  is  distinctly  green,  the  other  distinctly  blue 
[Moisture  absorbed  from  the  air  changes  blue  Co  C12  to  a  pale  pink 
almost  invisible  even  upon  white  paper].  The  ink  becomes  invisible 
again  when  the  papers  cool. 


Nickel  (sp.  gr.  8.9)  is  a  lustrous  white  metal,  taking  a 
high  polish.  It  is  used  for  plating  iron  to  protect  from 
rusting.  It  is  largely  used  in  alloys. 

Manganese  (sp.  gr.  8,  fus.  pt.  about  1800°)  is  a  hard 
brittle  metal.  It  easily  oxidizes  in  the  air  and  hence  is  not 
found  free.  It  is  best  kept  under  petroleum. 

Manganese  dioxide  (Mn  O.,,  see  preparation  of  O  and  Cl)  is  its 

most  important  ore.     Mangunutes  (grouping  Mn  O4")  and  perman- 
ganates (grouping  Mn.,  O8")  are  largely  used  as  disinfectants. 

EXP.  130. — Filter  (through  paper)  water  holding  small  quantities  of 
decomposing  organic  matter  in  solution,  (water  shaken  up  in  bottle 
from  EXP.  60  answers  well),  and  let  fall  into  it  a  few  drops  of  very  dilute 
potassium  permanganate  (K2  Mn.2  O8).  Place  beside  it  a  second  test 
tube  of  distilled  water  in  which  the  same  amount  of  permanganate  has 
been  put.  Leave  both  over  night.  The  permanganate  in  the  first  test 
tube  is  decolorized  having  given  up  a  part  of  its  O  to  the  organic  mat- 
ter. In  the  second  the  color  remains.  [The  presence  of  ierrous  salts, 
or  other  easily  oxidizable  substances,  must  be  avoided]. 

Potassium  permanganate  is  a  powerful  oxidizing  agent  and  is  a 
very  delicate  test  for  the  presence  of  decomposing  organic  matter.  [In 


£i,  Co,  Ni,  Mn,  Al,  and  Sn.  105 

such  tests  be  careful  not  to  add  too  much  K2  Mn,  O6  as  of  course  the 
excess  would  not  be  decolorized]. 


Aluminum  (or  aluminium,  sp.  gr.  2.6)  is  a  bluish-white 
metal,  taking  a  bright  polish.  It  does  not  readily  oxidize 
in  the  air.  It  would  be  very  extensively  used,  if  it  were 
not  for  its  high  price.  Delicate,  light  weights,  and,  in  gen- 
eral, instruments  needing  lightness  and  moderate  strength 
are  made  from  aluminum. 

Aluminum  bronze  (Cu  90  per  cent.,  Al  10  per  cent.)  is  a  very  hard 
alloy,  malleable,  has  the  color  of  gold  and  takes  a  fine  polish. 

A12  O3  occurs  in  corundum,  ruby,  sapphire  and  emery  (impure). 
Common  clay  is  chiefly  aluminum  silicate,  A12  Si2  O7,  (there  are 
numerous  silicate  "groupings"),  but  no  cheap  way  of  obtaining  the 
metal  has  yet  been  discovered.  Common  alum  is  a  double  sulphate 
(A12  K2  4  S  O4>  24  H2  O)  containing  much  water  of  crystallization. 
Ammonium  alum  (A12  (H4  N)2  4  S  64,  24  H2  O)  is  also  somewhat 
common.  Alum  is  much  used  in  dyeing  as  a  "mordant "  (see  DYEING). 
Cryolite  is  A12  F6  +  6  Na  F. 


Magnesium  (sp.  gr.  1.75,  fus.  pt.  about  2000°,  but  ignit- 
ing point  is  low,  the  Hame  of  a  candle  being  sufficient  to 
set  it  on  fire)  is  a  silver-  white  metal  not  found  native,  but 
in  combination  is  widely  distributed.  Mg  burns  in  the  air 
with  a  brilliant  light  (Exp.  2),  forming  Mg  O  (magnesia.  In 
general,  the  ending  a  means  (1)  the  oxide,  (2)  the  carbon- 
ate, (3)  the  hydrate  of  the  metal).  Its  light  is  rich  in 
chemical  (actinic)  rays,  and  hence  is  used  for  photographing 
in  dark  caves,  etc.  Arsenicum  is  never  found  with  it, 
and  the  metal  is  used  instead  of  Zn  in  important  tests 
for  As  (see  Marsh's  test). 


2  is  found  in  sea  water.  Mg  S  O4,  7  H2  O  (Epsom  salt)  is 
found  in  many  mineral  waters.  "Magnesia  alba"  is  an  artificial  mix- 
ture of  Mg  C  O3  and  Mg  2  H  O,  principally  the  former.  (See  magnes- 
ite,  hornblende,  meerschaum,  soapstone,  talc,  serpentine,  dolomite,  etc.  , 
in  cyclopaedia). 

8 


106  CHEMICAL  PRIMER. 


CHAPTER    XXXI. 


CALCIUM,    STRONTIUM,    AND    BARIUM. 

Calcium  (sp.  gr.  1.58)  is  a  ligKt-yellow  ductile  metal. 
It  oxidizes  in  moist  air  and  consequently  is  not  found 
native  (free).  Its  compounds  are  widely  diffused, 

Calcium  oxide  [Ca  O,  quicklime,  a  basic  oxide  (Exp.  4)] 
is  prepared  by  heating  the  native  carbonate  (Ca  C  O3)  in 
"kilns"  till  CO2  is  all  expelled. 

S 

CaCO3  =  CaO  +  C  O2 

It  is  used  for  making  mortar,  cements,  etc. 
CaO  +  H20  =  Ca2HO 

''water  slacked 
lime, "  mortar 

When  exposed  to  the  air,  this  absorbs  C  O2  and  hardens. 
Ca2HO  +  CO2  -  CaCO,  +  H2O 

"water  slacked  from  "air  slacked  evaporates 

lime"  air  liine" 

dried  mortar 

CaO  falls  to  a  powder  when  gradually  air-slacked  by  exposure. 
It  first  absorbs  water  and  then  C  O2  as  in  above  reactions. 

Ca  O  is  used  in  the  laboratory  for  drying  gases  (Exp.  45,  56,  and 
illuminating  gas)  and  in  the  "lime  light,  "-the  flame  of  the  oxy-hydro- 
gen  blowpipe  raising  it  to  the  wltite  heat  and  causing  it  to  emit  an  intense 
light. 

Calcium  carbonate  (Ca  C  O3)  is  found  as  marble,  limestone,  shells, 
(chalk  is  formed  by  beds  of  tiny  shells),  stalactites,  etc.,  also  with 
Ca3  2  PO4  in  bones  (see  HARD  WATER  and  EXP.  51).  Ca  S  O4  (anhy- 
drite, calcium  sulphate)  and  Ca  S  O4,  2  Ha  O  (gypsum,  plaster,  ala- 
baster) occur  native.  When  heated  to  120°,  gypsum  parts  with  its 
water  of  crystallization,  forming  *' plaster  of  Paris."  This  plaster 


CALCIUM,  STRONTIUM  AND  BARIUM.         107 


soon  hardens  ("sets")  when  mixed  with  water  and  hence  is  used  as 
cement,  and  for  taking  casts.  (See  WATER  permanently  hard).  Ca  C12 
has  so  strong  an  attraction  for  water,  that  it  is  deliquescent.  It  is 
used  for  drying  gases.  (See  BLEACHING  POWDER). 


Harilim  (sp.  gr.  4)  and  Strontium  (sp.  gr.  2.5)  resemble  calcium. 

EXP.  131. — Dissolve  a  bari- 
um salt  in  a  little  dilute  H  Cl 
and  making  a  loop  with  plati- 
num wire  introduce  into  the 
lower  and  outer  flame  of  Bun- 
sen's  burner.  The  flame  is 
colored  green, 

EXP.  132. — Pulverize  sepa- 
rately with  great  care 
Ba  2  N  O3  (oxidizing  and 
coloring  agent)  K  Cl  O3  (oxi- 
dizing agent)  and  gum  shellac, 
(C  and  H  principally,  combus- 
tible body).  Mix  carefully 
Fig.  35.— Green  Fire.  and  thoroughly  equal  bulk  of 

each  upon  piece  of  paper.     Place  in  small  mortar  and  ignite  using  the 

paper  as  a  fuse.     It  gives  green  fire. 

Barium  salts  are  used  to  give  the  color  in  green  fire 
[in  pyrotechny]  and  this  color  is  a  very  good  test  for  solu- 
ble or  volatilizable  salts  of  Ba. 

Heavy  spar  (Ba  S  O4)  is  often  used  to  adulterate  white  lead 
(F?bC  O3).  Ba  C12  is  test  for  soluble  sulphates.  (Exp.  96.) 

EXP.  133. — Repeat  EXP.  131,  using  Sr  salt  instead  of  Ba  salt.  The 
flame  is  colored  red, 

EXP.  1  ST.— Repeat  EXP.  132,  using  Sr  2  N  O3  instead  of  Ba2  N  O3. 
Red  fire  results. 

Strontium  salts  are  used  to  give  the  color  in  red  fire, 
and  this  color  is  a  very  good  test  for  soluble  or  volatilizable 
salts  of  Sr. 


108  CHEMICAL  PRIMER. 


CHAPTER    XXXII. 


POTASSIUM,   SODIUM,   AMMONIUM. 

Potassium  (sp.  gr.  .87,  fus.  pt.  63°)  is  a  light,  bluish- 
white  metal,  soft  enough  (at  15°)  to  be  spread  with  a 
knife. 

EXP.  135. — Cut  a  small  piece  of  clean  K  and  throw  upon  water  in 
beaker,  covering  with  glass  plate  (impurities  cause  spattering.) 

The  affinity  of  K  for  O  is  so  great  that  it  must  be  kept 
under  naptha  (Cle  H16  containing  no  O).  EXP.  135  proves 
that  it  cannot  be  found  free  or  native. 

The  compounds  of  K  are  widely  distributed.  They  are  constituents 
of  all  plants  and  of  the  bodies  of  animals.  K  H  O  (6i  caustic  pot- 
ash ")  is  a  white  solid  made  from  K2  C  O3  by  action  of  Ca  2  H  O 
(and  heat). 

K2CO3    -f    CaSHO     =    2KHO     -J-    CaCO3 

It  is  largely  used  in  the  manufacture  of  soap.  It  is  one  of  the 
strongest  alkalies  known.  (See  SOAP  and  ANTIDOTES). 

K.j,  CO3  ("  pearlash")  is  prepared  by  leaching  wood  ashes,  evapor- 
ating the  "  lye"  in  large  pots  (heuce  potash),  and  purifying  by  crys- 
tallization. It  is  a  deliquescent  salt,  with  a  strong  alkaline  reaction. 
It  (or  Na^CO3)  is  largely  used  in  chemical  analysis.  [See  ANA. 
CHARTS,  silver,  lead,  etc.]  It  reacts  with  insoluble  silicates  by  change 
of  partners. 

The  metallic  tassium  potassium     ,     The  metallic 

silicate       +    *  =    J  -j-     carbonate 

(insoluble)  (soluble.) 

H  K  CO;  (bicarbonate  of  potash,  "  saleratus,"  acid  salt  with 
alkaline  reaction)  may  be  prepared  by  passing  C  O2  through  strong 
solution  of  the  normal  salt  (K2  C  O3). 

H2  O    +    CO,    =    H2C03 
K»CO3    +    H2CO,    =    2HKC03 


POTASSIUM. 


109 


Potassium  nitrate  (KNO3  saltpetre,  nitre)  is  formed  by  the 
decomposition  of  refuse  organic  matter.  The  white  incrustation  often 
seen  about  such  matter  is  principally  K  N  O3.  It  is  a  strong  anti- 
septic, and  is  used  with  Na  Cl  (common  salt)  for  preserving  meat. 
It  is  largely  used  in  the  manufacture  of  gunpowder.  When  gun- 
powder burns,  the  reaction  may  be  represented  thus  : — 


2KNO 

solid 
oxidizing 


C3       =      K2S      -f-      N2      +      SCO, 


solid 

iibustible 
nhstance. 


solid 

combustible 
substance. 


ga»  at 
teinperatur 
of  explosioi 


Fireworks  are  composed  of  gunpowder  containing  an  excess  of  C 
and  S  with  coloring  matter. 

Potassium  chlorate  (K  Cl  O3)  is  a  good  oxidizing  agent.  (Exp. 
80  and  100,  and  MATCHES.  )  K2  Cr2  O7  forms  chrome  yellow  with  lead 
salts.  (ANA.  CHARTS.)  The  intensely  poisonous  K  C  N  dissolves  gold 
and  silver  cyanides  for  electroplating. 

K  Cl  resembles  Na  CL  Potassium  salts  are  largely  used  in  medi- 
cine. 


Sodium  (sp.  gr.  .97)  is  a  light,  silver-white,  soft  metal. 


EXP.  136.— Place  a  small 
clean  piece  of  Na  on  water 
and  quickly  press  below 
mouth  of  inverted  test  tube 
by  means  of  wire  gauze  at- 
tached to  wire.  The  water 
is  decomposed  and  the  H, 
set  free,  collects  in  test  tube. 
(If  Na  is  thrown  on  hot 
water  the  liberated  H  im- 
mediately takes  fire.) 


H. 


Fitr.  .'Hi. — Decomposing  Water 

Na    -|-    H2  O     —    Na  H  O    -f 

Sodium  resembles  K.  It  is  not  found  free  and  must  be 
kept  under  naptha.  It  is  used  as  a  reducing  agent  in  pre- 
paring Si,  B,  Mg,  and  A.l.  Sodium  imparts  a  yellow  tinge 
to  flame. 


110  CHEMICAL  PRIMER. 

EXP.  137.—  Repeat^Exp.  131,  using  sodium  salt  and  potassium  salt 
respectively  instead  of  barium  salt.  Sodium  gives  yellow  and  potassium 
purple  flame. 

Sodium  chloride  (Na  Cl,  common  salt)  is  the  most  abundant  of 
the  sodium  compounds.  It  is  the  source  from  which  most  compounds 
and  sodium  itself  are  obtained.  Its  distribution  in  larger  or  smaller 
quantities  is  almost  universal,  traces  which  the  spectroscope  reveals 
being  found  in  the  atmosphere.  It  is  obtained  from  immense  deposits 
or  beds,  from  saline  springs  and  sea-water  (by  evaporation).  It  crys- 
tallizes in  cubes  [Chap.  XXXIII].  It  is  one  of  our  most  common 
antiseptics. 

Sodium  sulphate  (Na-2  S  O4  10  H2  O,  Glauber's  salts)  is  remark- 
ably efflorescent. 

Sodium  carbonate  (Na2  C  O3  10  H_,  O,  sal  soda)  is  extensively 
used  in  the  arts.  It  is  made  by  Leblanc's  process  :— 

(1.)  Common  salt  and  sulphuric  acid  are'heated, 


2NaCl    -f    H,S04     =    Na2SO4    +    2HC1 

The  hydrochloric  acid  is  saved  by  being  absorbed  (See  EXP.  75,  70, 
and  comments)  in  tower  of  coke  wet  with  constantly  falling  water. 

(2.)  The  Na2  S  O4  is  heated  with  Ca  C  O3  (equal  wt.)  and  C  (half 
its  wt.  )  in  a  reverberatory  furnace. 

/ 
(a.)Na2S04    -f    C,  Na,  S    -f    SCO, 

reducing 

agent. 

(b.)NaaS    -f-    CaCO,  Na.2  C  O3    -f    CaS 

insoluble 


The  Na2  C  O3  is  then  washed  out  (lixiviated)  from  the  "  black 
ash"  and  purified  by  crystallization  (one  of  the  most  valuable  known 
means  of  purifying  crystallizable  solids). 

Acid  sodium  carbonate  (H  Na  C  O3,  bicarbonate  of  soda, 
"  soda"  of  cook-room)  has  alkaline  reaction,  and  is  prepared  by  pass- 
ing C  O2  into  the  normal  salt  (see  H  K  C  O3). 

Sodium  hydrate  (Na  H  O, .  caustic  soda)  is  made  from  sodium  car- 
bonate (just  as  K  H  O  from  K2  C  O3)  and  is  used  in  the  manufacture 
of  hard  soap. 

Sodium  nitrate  (Na  N  O3.  Chilian  saltpeter)  is  a  deliquescent  salt. 


AMMONIUM.  Ill 


Ammonium  (H4  N,  a  hypothetical  metal),  as  we  have 
seen,  is  a  compound  radical,  closely  allied  to  K  and  Na. 
It  has  never  been  isolated.  Its  salts  (H4  N  01,  sal  ammo- 
niac, H,NNO3,  (HaNJ.COa),  etc.,  and  its  hydrate 
(H4NHO,  c;  ammonia  water")  are  well  known  com- 
pounds (Exp.  37,  45,  and  ANTIDOTES). 


112  CHEMICAL  PRIMER. 


CHAPTER  XXXIIL 


THE   ALLOYS,  SPECTRUM  ANALYSIS,   AND 
SYSTEMS   OF   CRYSTALLIZATION. 

The  most  important  alloys  (with  their  usual  proportions)  are  : — 

Aluminum  Bronze Cu  (9)  Al  (1) 

Bell-Metal Cu  (9)  Sn  (2) 

Brass . .  .Cu  (2)  Zn  (1) 

Bronze Cu  (95)  Sn  (4)  Zn  (1) 

Coin  (Gold) Au  (90)  Cu  (9)  Ag  (1) 

Coin  (Silver) Ag  (9)  Cu  (1) 

Fusible  Metal Bi  (see)  Pb  Sn 

German  Silver Cu  (5)  Zn  (2)  Ni'(2) 

v brass ' 

Hard  Solder Cu  (1)  Zn  (1) 

Pewter Sn  (4)  Pb  (1) 

Phosphor-Bronze Cu  (88)  Sn  (10)  P  (1.5)  Pb  (.5) 

Shot Pb  (99.5)  As  (.5) 

Soft  Solder Pb  (1)  Sn  (1) 

Type-Metal Pb  (70)  Sb  (20)  Sn  (10) 


The  spectroscope,  next  to  the  balance,  is  the  most  useful  instrument 
for  original  chemical  research.  It  consists  of  a  prism,  mounted  upon 
a  stand,  carrying  a  tube  with  tine,  adjustable  slit,  through  which  light 
(the  rays  being  made  parallel  by  a  lens)  falls  upon  the  prism.  The 


.  THE  SPECTROSCOPE.  113 

light,  refracted  by  the  prism,  is  received  by  a  small  telescope,  which 
magnifies  the  spectrum  ("rainbow,"  if  solar  spectrum,  i.  e.,  if  light  is 
sunlight)  before  it  reaches  the  eye.  The  spectrum  of  the  sun  has  dark 
lines  (Fraunhofer's  lines),  crossing  it  at  right  angles  all  along  from 
the  red  to  the  violet  portion,  but  at  irregular  intervals.  The  relative 
position  of  these  lines  has  been  accurately  determined. 

If,  instead  of  sunlight,  the  light  from  the  sodium  flame  (Exp.  137) 
enters  the  slit  no  colored  bands  from  red  to  violet,  as  in  the  solar 
spectrum,  are  seen.  Instead,  the  spectrum  is  totally  dark  except  a 
brilliant  yellow  line  (d  >uble)  crossing  the  spectrum  where  before  (in 
solar  spectrum)  was  the  dark  line  D  (double).  If  the  light  of  the 
potassium  flame  enter  the  slit,  three  lines  appear  on  the  dark  spectrum : 
a  bright  purplish  line  at  (what  was  before)  the  violet  end,  and  at  the 
other  end  two  red  lines — the  outer,  bright ;  the  inner,  faint. 


Spectra  of 


Red 


range  Yellow     Green  Blue    Indigo  Violet 


A    B  D  E    b 


Yellow  line. 


Sun  with 

few  dark  lines 

shown. 


Sodium. 


Potassium. 


Red  lines.  Purplish  line. 


All  the  other  metals  and  non-metals  have  characteristic  spectra,  but 
some  substances  require  more  heat  than  the  flame  of  the  Buusen's 
burner  to  volatilize  them,  and  the  electric  flame  is  used.  With  a 
small  spectroscope  the  student  can  easily  obtain  the  spectra  of  Na, 
K,  Ba,  Sr,  Co,  and  other  metals  whose  chlorides  are  easily  volatil- 
ized. Many  rare  metals  have  been  discovered  by  means  of  the  spec- 
troscope (caesium,  rubidium,  thallium,  indium,  etc.).  By  it  the  light 
of  the  heavenly  bodies  reveals  the  presence  in  those  far-off  suns  of 
many  elements  common  upon  the  earth  (Celestial  Chemistry). 


114  CHEMICAL  PRIMER^ 

Most  chemical  substances,  when  they  pass  from  the  liquid  to  the 
solid  state,  assume  some  definite  form  and  are  said  to  crystallize  (see 
EXP.  34  and  connection).  It  has  been  found  possible  to  arrange  all 
crystals  in  six  systems,  according  to  the  arrangement  of  their  sides 
and  angles  around  certain  imaginary  axes,  intersecting  at  the  center  of 
the  crystals.  These  axes  are  shown  only  in  Plates  I  and  n  of  Fig.  37. 

1.  Regular  System.— Three  axes  all  equal  and  all  at  right  angles. 
Plates  i,  n,  and  Hi.  Ex. :  Common  salt,  alum,  garnet. 

2.  Hexagonal   System. — Four  axes,  three  equal  and  in  one  plane, 
making  angles  of  60°,  and  one,  longer  or  shorter,  at  right  angles  to  the 
plane  of   the  other  three.       Plates  iv  and  v.     Ex.:    sodium   nitrate, 
quartz,  and  ice. 

3.  Quadratic    System. — Three  axes  all  at  right  angles,  and  one 
shorter  or  longer  than  the  other  two.     Plates  vi  and  vn.     Ex.:  Potas- 
sium ferrocyanide  and  tin  dioxide. 

4.  Rhombic   System. — Three   axes   all  unequal   and  all   at   right 
angles.     Plates  vin  and  ix.     Ex. :  potassium  nitrate,  barium  sulphate, 
and  sulphur,  crystallized  from  solution  in  carbon  bisulphide. 

5.  Monoclinic  System. — Three  axes  all  unequal.     Two  cut  each 
other  obliquely,  and  one  is  at  right  angles  to  the  plane  of  the  other 
two.      Plate  x.      Ex. :    Sodium  carbonate,   sodium  phosphate,  ferrous 
sulphate,  borax,  cane  sugar,  and  sulphur  from  fusion. 

6.  Triclinic   System. — Three   axes,    all   unequal  and  all  oblique. 
Plates  xi  and  xn.     Ex. :  copper  sulphate,  manganese  sulphate,  boracic 

fvirl    o-nrl    -rvrk-f  aaoii-iTYfc     VYI  r»V*  YTkm  a+.A 


acid  and  potassium  bichromate. 


Certain  substances,  like  S,  crystallize  in  two  systems,  and  are  said  to 
be  dimorphous.  A  very  few  substances  are  trimorphous.  Anything 
without  crystalline  form  is  amorphous  (as  'plastic  sulphur).  Different 
substances  that  crystallize  in  the  same  form  are  isomorphous  (as  com- 
pounds of  the  halogens  with  the  same  metal).  A  crystalline  body 
splits  more  readily  in  a  certain  direction  than  others.  This  splitting  is 
called  cleavage.  The  powder  of  a  crushed  or  scratched  mineral  is  called 
its  streak. 


THE  ALLOYS. 


115 


Fig.  37. 


1 10  CHEMICAL  PRIMFAt. 


CHAPTER    XXXIV. 


STARCH,  SUG-AR,   ETC. 

ORGANIC  chemistry  treats  of  those  compounds  (composed 
principally  of  C,  H,  N,  and  O,  but  all  containing  C  and 
H)  which  are  formed  chiefly  by  animals  or  plants  in  their 
processes  of  growth  or  partial  decay  No  line  can  be 
sharply  drawn  between  organic  compounds  and  inorganic. 
Many  compounds  which  formerly  were  supposed  to  be  pro- 
duced only  by  the  "  vital  force"  of  the  plant  or  animal, 
have  been  formed  recently  in  the  laboratory. 

As  a  rule,  inorganic  substances  have  few  atoms  in  the  molecule, 
while  molecules  of  organic  substances  frequently  contain  a  very  large 
number  of  atoms.  Often  different  organic  substances  contain  the 
same  elements  in  the  same  proportion.  Thus  the  "empirical  forlhula'' 
(expressing  only  the  proportions  of  the  elements)  of  cane  suyar  is  pre- 
cisely the  same  as  that  of  gum  arabic,  namely:  Ci2  H22  On.  This 
peculiar  relation  is  called  isomeiism.  Butyric  acid  and  ethyl  acetate, 
two  well-known  compounds,  are  isomeric,  having  the  empirical  for- 
mula: C4H8O2,  but  the  "rational  formula"  (which  attempts  to  rep- 
resent in  some  way  the  «rr<tn</<'inent  of  the  atoms  in  the  molecule)  of 

Butyric  acid=H  C4  H7  O2.     (KEF.  TAJ-.LE  No.  2,  Continued.) 
Ethyl  acetate=C2  H5  C.2  H3  O2.     (.KEF.  TABLE  No.  2.) 

Plants  in  general  prepare  food  for  animals  from  the 
mineral  kingdom,  and  animals,  after  using  it,  return  it  to 
the  mineral  kingdom  again.  The  organic  by  complete 
decay  returns  to  the  inorganic.  The  sun's  light  and  heat 
(Exp.  58)  is  the  motive  power  by  which  the  plant  is  en- 
abled to  build  up  the  organic  out  of  the  inorganic. 


STARCH.  117 

Starch  (C6-H10  O5)  is  a  substance  found  in  all  grains, 
in  many  roots,  stems,  and  fruits.  It  is  composed  of  grains, 
which  the  microscope  reveals  differing  in  size  and  shape  in 
different  plants.  These  grains  swell  up  and  burst  on  heat- 
ing with  water.  Its  use  for  food,  in  the  laundry,  etc.,  is 
well-known.  Arrow-root  and  tapioca  are  varieties  of 
starch  from  roots  of  tropical  plants.  Sago  is  starch  from 
the  pith  of  the  sago-palm. 

The  test  of  starch  is  iodine,  with  which  it  forms  a  blue  compound. 
(Exp.  84.) 

EXP.  138. — Scrape  some  potato  into  cold  water  and  squeeze  through 
a  linen  cloth  several  times.  The  insoluble  starch  remains  suspended  in 
the  filtrate,  while  the  woody  fiber  (cellulose)  remains  upon  the  filter. 
After  subsidence,  pour  off  the  water,  and  dry.  This  illustrates  the 
method  of  obtaining  starch  from  the  potato. 

When  starch  is  heated  to  about  205°,  it  changes  into  an  isomeric 
compound,  dextrin,  much  used  instead  of  gum  arabic  in  making  adhe- 
sive stamps.  Dextrin  is  also  formed,  if  starch  is  boiled  with  water 
slightly  acidulated  with  sulphuric  acid.  If  the  boiling  is  continued 
longer,  the  dextrin  is  converted  into  starch-sugar  (Ct;Hl2  O6).  Dextrin 
gives  no  blue  color  with  iodine. 

Gum  arabic  (C12  H22  Ou)  exudes  from  a  species  of  acacia.  Pectose 
is  a  gummy  substance  found  in  many  fruits  and  vegetables. 

Cellulose  (C18  H30  O15),  or  woody  fiber,  is  the  frame-work  of  the  cells 
of  plants,  and  is  found  in  every  part,  even  in  the  pulpy  fruits.  Linen, 
made  from  the  inner  bark  of  flaxj  and  cotton — the  hollow  white  hairs 
around  the  seed  of  the  cotton  plant — are  nearly  pure  cellulose  (see 
cyclopaedia).  If  paper  is  dipped  in  dilute  sulphuric  acid  for  a  few 
moments,  tough  parchment  paper  results. 

Gun-cotton  is  cellulose,  in  which  part  of  the  H  Jias  been  replaced 
by  the  negative  radical  N  O2,  by  dipping  in  a  mixture  of  H  N  O  ;  and 
H2  S  O4.  It  is  very  explosive. 

Gun-cotton,  dissolved  in  ether  (ethyl  oxide)  and  alcohol  (ethyl 
hydrate)  forms  collodion,  much  used  by  photographers. 

Celluloid  is  made  from  gun-cotton  and  camphor,  by  submitting  to 
great  pressure.  It  can  be  colored  in  imitation  of  coral,  made  into  col- 
lars and  cuffs,  and  substituted,  in  general,  for  ivory.  Its  manufacture 
is  comparatively  a  new  industry. 


118  CHEMICAL  PHIMER. 

Cane-Sugar,  Sucrose,  (C,,  H,2  Ou)  may  be  obtained 
from  the  sugar-cane,  beet- root,  maple,  and  certain  kinds  of 
palm.  In  making  it  from  the  sugar-cane  (1)  the  canes  are 
crushed,  (2)  lime  (Oa  O)  is  added  to  the  juice  to  neutral- 
ize any  acid  formed  by  fermentation,  (3)  the  liquid  is 
evaporated  to  jelly,  (4)  set  aside  to  cool ;  (5)  the  sugar 
crystallizes,  forming  brown  sugar,  (6)  it  is  put  into  per- 
forated casks  to  drain.  The  drainings  ("  mother  liquor") 
are  molasses. 

In  the  process  of  refining,  brown  sugar  is  (1)  dissolved, 
(2)  pumped  to  upper  story  of  the  high  building,  (3)  filtered 
through  twilled  cotton  bags,  kept  in  bath  of  steam,  (4) 
filtered  through  animal  charcoal  (Exp.  48),  (5)  evaporated  in 
"vacuum  pans"  (kettles  from  which  air  is  partially  re- 
moved by  pump,  so  that  the  syrup  boils  at  a  lower  temp- 
erature and  does  not  burn),  and  (6)  set  aside  to  crystallize. 
If  in  moulds,  loaf-sugar  results;  if  in  centrifugal  machines, 
granulated.  The  drainings  are  syrup  or  sugar-house 
molasses.  (Exp.  08.) 

Caramel  is  sugar  carefully  "burnt"  so  that  it  loses  part  but  uot  all 
its  water.  It  is  used  for  coloring  liquors,  flavoring  confectioneries,  etc. 

Cane-Sugar  is  not  found  in  animal  tissues  or  secretions,  but  is 
changed  in  the  alimentary  canal  before  absorption  into  grape  sugar. 

Grape-SUgar  (C6Hl2O(i)  glucose,  (dextrose,  starch-sugar,  fruit- 
sugar)  is  found  in  honey,  figs,  grapes,  and  many  kinds  of  fruit.  It  has 

much  less  sweetening  power  than  cane-sugar. 

• 

EXP.  139. — To  a  solution  of  grape-sugar  (made  by  boiling  a  few 
raisins  in  water  and  filtering)  add  three  drops  of  copper  sulphate  (5  per 
cent,  solution  and  slightly  acidulated  with  acetic  acid),  then  add  strong 
solution  of  K  H  O  (potash  or  Na  H  O,  soda)  till  the  light  blue  color 
of  liquid  becomes  darker.  Raise  to  the  boiling  point,  but  do  not  boil 
beyond  a  few  seconds.  A  yellowish-red  precipitate  of  cuprous  oxide 
(Cu2  O)  falls.  This  is  a  delicate  test  for  sugar  in  animal  secretions 
(grape-sugar,  or  milk-sugar  isomeric  with  cane).  (See  ADD.  EXP.) 


FERMENT  A  TION.  1 19 

EXP.  140. — Divide  a  solution  of  cane-sugar  into  two  parts;  apply 
test  as  in  EXP.  139,  no  cuprous  oxide  falls.  Slightly  acidulate  the 
second  portion  with  H2  S  O4,  and  boiling  for  ten  minutes,  the  cane- 
sugar  changes  to  grape-sugar.  Apply  test,  and  Cu2  O  falls.  Boil  for 
some  time  a  minute  quantity  of  starch  in  dilute  (2  per  cent. )  sulphuric 
acid.  The  starch  changes  to  grape-sugar.  Divide  into  two  portions 
and  test  the  first  by  iodine;  no  starch  is  found.  Test  the  second, 
grape-sugar  is  found.  Boil  cellulose  (woody  fiber  free  from  pitch)  in 
dilute  H2  S  O4  and  grape-sugar  is  found  in  the  solution. 

The  insoluble  starch  laid  up  in  the  seeds  of  plants  is 
converted  into  (soluble)  sugar  by  the  action  of  a  nitrogen- 
ous substance,  called  diastase,  in  the  presence  of  warmth 
and  moisture.  The  sugar  is  then  absorbed  by  the  growing 
plantlet.  and  is  built  into  its  structure  as  woody  fiber,  etc. 


Fermentation  is  a  species  of  decay.  A  necessary  con- 
dition is  the  presence  of  some  nitrogenous  ("albuminous") 
substance,  called  a  ferment,  and  the  growth  therein  of  a 
fungus  plant  called  yeast.  This  plant  is  of  a  low  order, 
and  spreads  by  the  rapid  multiplication  of  cells  throughout 
the  whole  fermenting  substance,  if  it  has  the  needed 
warmth  (about  73°)  and  moisture.  In  the  fermentation 
of  substances  containing  grape-sugar  (or  cane-sugar  which 
changes  to  grape-sugar),  there  are  two  stages: — 

1.  The  Alcoholic  Fermentation,   in  which  the  sugar 
breaks  up  into  alcohol  and  carbonic  oxide. 

C6  H12  O6     =     2  C,  H5  H  O     +     2€  O2 

grape-  sugar.  alcohol.  carbonic 

oxide. 

2.  The  Acetic  Fermentation,  in  which,  by  exposure  to 
the  air,  the  alcohol  is  oxidized,  forming  acetic  acid  and 
^vater. 

C2H5HO     +     02  HC2H302     +     H20 

ethyl  hydrate.  from  the  acetic  acid.  water. 

air. 


120  CHEMICAL  PRIMER. 

Beer,  ale,  etc.,  are  made  from  malt  (grain,  that  has  germinated  suf- 
ficiently to  change  nearly  all  the  starch  to  sugar,  and  in  which  the  fer- 
mentation has  been  checked  by  drying).  The  malt  is  crushed,  and 
water,  hops,  and  yeast  added,  when  the  alcoholic  fermentation  at  once 
commences. 

Wine  is  made  by  the  fermentation  of  grape  juice.  .If  all  the  sugar 
is  converted  into  alcohol  and  C  O.2,  dry  wine,  results.  If  the  fermenta- 
tion is  checked  (by  boiling,  or  by  an  antiseptic,  or  both),  when  only 
part  of  the  sugar  is  changed,  sweet  wine  results.  Effervescing  wine 
is  sealed  in  strong  bottles  while  the  alcoholic  fermentation  is  going  on. 

When  any  fermented  liquor  is  distilled,  the  alcohol  (having  a  lower 
boiling  point  than  water)  passes  over  through  the  condenser  (Fig.  16) 
first,  together  with  certain  flavoring  substances  and  a  certain  part  of 
the  water.  Brandy  is  made  by  distillation  from  wine,  rum  from  fer- 
mented cane-juice,  wliiskey  from  fermented  corn,  rye,  or  potatoes,  gin 
from  fermented  barley  and  rye,  and  afterwards  distilled  with  juniper- 
berries  (flavoring). 

Alcohol  (C.,H5  HO  ethyl  hydrate)  is  the  intoxicating  principle  of  all 
varieties  of  (unadulterated)  "liquors."  It  is  a  colorless,  volatile,  inflam- 
mable, poisonous  liquid.  Its  flame,  as  we  have  noticed,  is  hot  and 
smokeless.  It  is  a  valuable  solvent.  Many  substances,  as  resins,  etc., 
insoluble  in  water,  are  soluble  in  alcohol.  4  A  solution  of  a  substance 
(medicinal)  in  alcohol  is  a  tincture.  (See  VOLATILE  OILS. )  Strong 
alcohol  contains  about  10  per  cent,  water,  which  cannot  be  removed  by 
distillation.  It  may  be  removed  by  Ca  O,  or  some  other  substance 
which  has  a  great  affinity  for  water,  when  anhydrous,  or  absolute 
alcohol,  remains.  Common  alcohol  belongs  to  marsh  gas  series. 

EXP.  .141. — Anhydrous  (white)  CuSO4  (Exp.  34)  is  test  for  absolute 
alcohol.  If  water  is  present,  the  sulphate  turns  blue.  Apply  the  test. 

Common  Ether,  (C2  H^  O,  ethyl  oxide,  is  made  by  distilling  alco- 
hol in  presence  of  sulphuric  acid.  It  is  a  very  volatile,  inflammable 
liquid.  It  produces  great  "cold"  by  its  evaporation.  If  blown  in  a 
fine  spray  (from  atomizer)  upon  some  part  of  the  body,  the  rapid  cool- 
ing produces  local  anaesthesia  (by  "freezing"  the  spot.)  It  is  inhaled  as 
an  Anaesthetic,  and  is  a  valuable  solvent.  . 

There  is  a  large  number  of  alcohols  (hydrates  of  positive  radicals)  and 
corresponding  ethers  (oxides)  arranged  in  series.  Methyl  Alcohol, 
(C  H-j  H  O,  wood  spirit),  is  formed  by  the  destructive  distillation  of 
wood,  and  resembles  ethyl  or  common  alcohol  in  many  particulars. 


ALCOHOL,  ETC.  121 


Ainyl  Alcohol  (C5  Hn  H  O,  fusel  oil),  has  a  very  fetid  odor,  and  is 
much  more  poisonous  than  C2  H5  H  O.  It  is  formed  in  small  quanti- 
ties in  the  fermentation  of  potatoes  and  grain.  Its  boiling  point  is  137°, 
while  that  of  ethyl  alcohol  is  only  78°.  The  common  alcohol  is  separ- 
ated from  it  by  fractional  distillation,  a  valuable  method  of  separ- 
ating liquids  whose  boiling  points  differ  materially. 

The  salts  of  the  positive  groupings  of  the  ethers,  or  alcohols,  are 
often  termed  "  compound  ethers,"  (Ex.:  ethyl  nitrate,  C2H5NO^, 
etc.).  Many  of  these  "compound  ethers"  are  sold  as  "essences," 
and  they  very  closely  imitate  the  true  essences,  Ethyl  butyrate 
(C,H5  C4  H7  O2)  is  sold  as  "essence  of  pine-apple." 

Chloroform  (C  H  C13)  is  made  by  distilling  alcohol  with  "chlo- 
ride of  lime."  It  is  a  colorless,  volatile  liquid,  used  as  an  anaesthetic 

and  as  a  solvent. 

Chloral  (C2  H  C13  O),  a  colorless,  oily  liquid,  is  made  by  passing  dry 
chlorine  into  alcohol.  It  .combines  with  water  of  crystallization, 
forming  a  white  crystalline  substance,  the  so-called  chloral  hydrate 
(C-2  H  C13  O  H2  O).  Chloral,  when  taken,  reacts  with  the  alkali  of,  the 
blood,  producing  chloroform  and  inducing  sleep.  It  is  much  used  in 
medicine. 

Acetic  Acid  (H  C2  H3  O2,  the  acid  of  vinegar),  as  we  have  seen,  is 
produced  by  the  fermentation,  under  the  proper  conditions,  of  sub- 
stances containing  sugar.  It  is  produced  in  the  second  stage,  by  the 
oxidation  of  alcohol.  Strong  acetic  acid  crystallizes  at  17°  and  is  called 
glacial.  The  "mother"  of  vinegar  is  a  fungus  plant;  it  assists  the 
fermentation  by  absorbing  O  from  the  air  and  giving  it  up  to  oxidize 
the  alcohol.  When  the  alcohol  is  all  gone,  however,  it  works  mischief 
by  oxidizing  and  destroying  the  vinegar  itself  (destructive  fermenta- 
tion). Sulphuric  acid  and  pungent  spices  are  often  added  to  vinegar  to 
increase  its  strength. 


Carbolic  acid  (C6H5HO,  phenyl  hydrate),  better  classed  with 
the  alcohols  (of  phenyl  series),  is  obtained" from  coal-tar.  It  is  a  very 
poisonous  liquid  (it  may  be  obtained  crystallized)  and  is  a  powerful 
antiseptic  and  disinfectant.  Carbolic  acid  is  sometimes  confounded  with 
creosote  (C8  H10  O2),  the  antiseptic  principle  of  smoke  (by  which 
"bacon,"  etc.,  is  "cured")  ;  indeed,  impure  carbolic  acid  is  commonly 
called  creosote. 

9 


122  CHEMICAL  PRIMER. 


Benzol  (C6H5H,  phenyl  hydride—  see  ILLUMINATING  GAS)  is  a  very 
volatile,  inflammable  liquid,  is  a  valuable  solvent,  and  is  used  to  remove 
grease  spots  from  silk  and  woolen  articles.  From  it,  by  the  action  of 
nitric  acid,  uitrobenzol  (C6H5NO2),  an  oily  liquid  is  prepared.  By 
the  action  of  reducing  agents  upon  iiitrobenzol  the  celebrated  aniline 
(C6H7N),  the  source  of  the  "coal-tar"  dyes,  is  prepared  (see  DYE- 


(For  tar,  coal-tar,  naptha,  kerosene  oil,  dead-oil,  petroleum,  bitumen, 
etc.,  see  cyclopaedia.  ) 


There  are  three  great  classes  of  (organic)  foods :  — 

1.  Starch,  or  sugar  and  allied  bodies. 

2.  Oleaginous  substances.     (See  Chap,  xxxvn.) 

3.  Albuminous  substances  ("nutritious  matter,"  nitro- 
genous matter.) 

Albumen  (formula  very  complex,  C..  H..  N..  S.,  O..)  is  found  nearly 
pure  in  white  of  eggs.  Albuminous  matter  possesses  the  power  of  (]) 
becoming  a  ferment,  (2)  of  coagulation,  and  (3)  of  putrefaction.  Casein 
is  found  in  milk,  and  is  coagulated  by  rennet  (acid);  gluten,  in  flour, 
meal,  etc.;  fibrin,  in  blood,  and  another  variety  of  fibrin  in  muscular 
tissue.  (See  ADD.  EXP.) 

EXP.  142. — Soak  a  small  bone  over  night  in  H  Cl  (30  percent.).  The 
mineral  matters  are  dissolved,  and  the  soft  animal  matter  left.  Wash 
thoroughly  in  water  and  leave  in  water  over  night  again.  Boil  the 
animal  matter  for  some  time  in  a  small  quantity  of  water  and  set  aside 
to  cool.  A  gelatinous  substance  remains. 

Gelatin  (formula  complex;  a  nitrogenous  substance  not  belonging  to 
albuminous  matter  proper)  is  formed  by  the  action  of  hot  water  upon 
animal  membranes,  tendons,  and  bones.  Glue  is  very  impure  gelatin. 
Isinglass  is  very  pure  gelatin  from  the  air-bladders  of  fish.  (The 
mineral,  mica,  used  in  the  doors  and  sides  of  parlor  stoves,  is  often  im- 
properly called  isinglass). 

Flour  consists  of  gluten,  starch,  and  a  little  dextrin  and  sugar. 
(The  oily  and  mineral  substances  are  contained  chiefly  in  the  bran  of 
the  grain,  hence  "coarse  food,"  as  corn  meal,  graham  flour,  oatmeal, 
cracked  wheat,  etc.,  are  very  necessary  for  the  proper  development  of 
bone  and  sinew.)  In  bread-making  the  flour,  mixed  with  milk  (or  water), 
containing  yeast,  is  set  in  a  warm  place,  and  immediately  fermenta- 


VEGETABLE  ACIDS.  123 

tioii  begins.  The  C  O2  set  free  is  held  by  the  gluten,  causing  the 
dough  "to  rise."  This  is  kneaded,  to  distribute  evenly  the  fermenta- 
tion and  to  break  up  the  large  bubbles  of  C  O2.  In  baking,  the  C  O2 
and  alcohol  escape.  If  the  oven  is  too  hot,  a  crust  forms  too  quickly, 
prevents  the  escape  of  the  C  O2,  and  large  cavities  are  formed.  If  the 
fire  is  not  hot  enough,  the  C  O2  escapes  before  the  cells  are  sufficiently 
hardened,  and  the  bread  falls.  Sour  bread  is  formed  when  before  (or 
while)  baking  the  second  stage  (acetic)  of  fermentation  is  reached. 
Saleratns  (H  K  C  O3),  or  Soda  (H  Na  C  O3),  is  added  to  prevent 
this  by  neutralizing  any  acid  that  may  form.  In  raising  biscuit,  "soda" 
and  '  'cream  of  tartar"  (H  K  C4H4O6)  are  used  to  furnish  the  C  O2,  while 
the  salt  that  remains  is  a  harmless  one.  Common  Baking  Powder  is 
merely  "cream  of  tartar"  and  "soda,"  but  it  is  often  adulterated  with 
alum,  to  make  inferior  flour  look  white.  Bread  containing  alum  is  highly 
injurious,  producing  chronic  constipation.  (See  ADD.  EXP.)  "Yeast 
Cakes"  are  made  by  exposing  moistened  corn  meal,  containing  a  ferment, 
to  moderate  temperature  till  the  gluten  is  in  the  midst  of  the  alcohol 
fermentation.  The  fermentation  is  then  checked  by  drying.  The 
yeast  plant  (fungus)  throughout  the  cake  may  be  likened  to  so  much 
dry  seed,  which  needs  only  to  be  sown  in  the  right  soil  (in  the  dough). 
[The  chemical  changes  in  the  body  (Physiological  Chemistry)  are  too 
difficult  for  insertion  in  a  primary  work.] 


CHAPTER   XXXV, 


VEGETABLE  ACIDS  and  BASES  (ALKALOIDS). 


Compounds  of  ^oxalic  acid  (H2  C2  O4  2  H,  O),  especially  K2  C2  O^, 
and  Ca  C2  O4  are  found  in  rhubarb,  sorrel,  etc.  (also  a  very  little  of  the 
free  acid.)  The  acid  is  a  powerful  poison.  It  is  sold  as  "salts  of 
lemon"  (a  danger  ow  name),  to  remove  ink  stains. 


Pe32C^H^O^  +  3H.2C,04   =  2H3C^~H^O^  +3FeC2(>4 

iron  taimate  oxalic  acid  tanuic  acid  iron  oxalate 

(ink)  acid  (soluble) 

The  iron  oxalate   and   tannic   acid   formed   should  be  immediately 
washed  out  of  the  cloth,  else  the  cloth   will  be  corroded.     Oxalic  acid 


124  CHEMICAL  PRIMER. 

readily  dissolves  metallic  oxides,  forming  oxalates,  and  hence  is  used  to 
clean  brass  and  copper,  and  to  remove  spots  of  iron-rust.  It  is  made 
on  a  large  scale  by  heating  sawdust  and  caustic  potash  (K  HO). 


Salts  of  tartaric  acid  (H2  C4  H4  O6),  also  minute  quantities  of  the 
free  acid,  exist  in  many  fruits,  and  especially  in  the  grape  (as  acid 
potassium  tartrate,  H  K  C4H4O6).  It  settles  during  fermentation,  form- 
ing a  crust  ("argol,"  "bitartrate  of  potash")  which,  when  puritied,  is 
cream  of  tartar  (HKC^H^Og).  Tartar  emetic  is  a  double  salt: 
potassium  antimonyl  tartrate  (K  Sb  O  C4  H4  O,;).  Rochelle  salt  is 
(KNaC4H40(i) 


Citric  acid  (H3  €«  H5  O7  H2  O)  is  the  acid  of  the  lemon,  lime,  etc. 
Its  salts  are  also  present. 


Malic  acid  (H3  C4  H3  O5)  occurs  (together  with  potassium  malate) 
in  most  unripe  fruits,  especially  unripe  apples. 

Tanilic  acid  (Hd  C27  H19  O17 — tribasic?),  or  tannin,  is  found  in  the 
leaf  and  bark  of  most  trees  and  of  many  shrubs  (oak  especially,  in  nut 
galls,  hemlock,  etc.),  together  with  a  little  gallic  acid  (H3C7H3O5,  H2O). 

EXP.  143. — To  a  solution  of  tannic  acid  add  a  solution  of  gelatin  ;  a 
yellowish-white  precipitate  of  gelatin  tannate  falls. 

In  the  process  of  tanning,  the  tannic  acid  unites  with 
the  gelatin  of  the  hide,  forming  a  tough  compound 
(leather). 

EXP.  144. — To  a  solution  of  tannic  acid  add  copperas  solution.      Ink 
is  formed,  becoming  darker  by  exposure  to  the  air.     (Ous  salts  of  Fe 
have  a  tendency  to  oxidize  and  form  peculiar  and,  as  a, rule,  less  soluble 
"oxy-salts. ") 
3FeSO4  +  2H3C27H19On    =    Fe3  2  C27  H,9  O17  +3H2SO4 

copperas  tannic  acid  INK  corrodes  pens. 

Leather  is  blackened  by  washing  one  side  with  solution  of  iron  sul- 
phate, thus  covering  it  with  ink.  Creosote  or  corrosive  Miblimate 
(Hg  C12),  antiseptics,  are  used  to  keep  ink  from  moulding. 


The  alkaloids  are  organic  bases  (see  comments  EXP.  3 
and  4)  and  they  form  salts  on  the  ammonia  type.  Many 
of  them  have  a  bitter  taste,  are  powerful  poisons,  and 
valuable  medicines  (see  ANTIDOTES).  The  liquid  alkaloids 


ALKALOIDS. 


125 


(few)  contain  C,  H  and  N,  while  the  solid  (nearly  all)  con- 
tain C,  H,  N,  and  O.  Their  salts  eoccur  in  the  plants 
from  which  the  are  obtained. 


XOTE.  —  The  theory  of  types  has  done  much  to  advance  the  science 
of  chemistry.  The  pupil,  however,  must  distinguish  between  theory 
a,ndfact.  The  formation  of  compounds  on  the  water  type  is  strictly 
represented  thus:  — 


H 
H 


O     =     water 


N02 
H 


O     —     nitric  acid 


in  which  the  negative  radical,  iiitryl  (N  O.,),  replaces  an  atom  of  H  in 
the  molecule  of  water.     So: — 

SO, 


I: 


O.,     =     two  molecules  of  water, 


O.,     =       sulphuric  acid 


in  which  two  atoms  of  H  in  the  water  have  been  replaced  by  the  neg- 
ative radical  sulphury  1,  S  O2.  The  reaction  in  EXP.  15,  written  strictly 
to  represent  the  water  type,  becomes: — 


Na 
H 


O     -f 


C .,  H3  O 
H 


H 
H 


It  is  easily  seen  how  the  negative  radical,  usually  considered  by 
chemists  as  the  replaceable  and  replacing  quantity  in  reactions,  is  ob- 
tained from  the  negative  "grouping,"  viz. :  by  subtracting  one  atom  of 
O  from  monad  groupings,  two  from  dyad  groupings,  etc.  Negative 
radicals  usually  take  the  termination,  yl.  Again,  binary  acids  and  salts 
can  not  in  any  strict  senxe  be  referred  to  the  water  type  as  in  this  book, 
but  must  be  referred  to  the  hydrochloric  acid  type.  The  formation  of 
compounds  on  the  ammonia  type  is  shown  in  the  following  formulas, 
the  connecting  element  being  the  triad,  nitrogen.  The  examples  given 
are  artificial  compounds  (alkaloids)  : — 


H 
H 
H 


N      —     ammonia          H 
H 


phenyl-   C,H5 

N     amiiie  H 

(aniline)        H 


N  ethylamine 


0,5 


N     dieth  y  1  -  amin  e 


C2H5 


N     triethyl-amine. 


If  the  H  of  ammonia  (one  or  more  atoms)  is  replaced  by  a  positive 
radical,  an  amine  results;  if  by  a  negative  radical,  an  amide;  if  a  pos- 
itive and  a  negative  both  take  part  in  the  replacement,  an  aikalamide — 
all  giving  rise  to  very  hard  na'mes.  The  ammonia  type  should  be 


126  CHEMICAL  PRIMER. 

considered  only  in  this  respect  by  beginners.  Ammonia  forms  salts 
•with  the  acids,  without  replacing  the  hydrogen  of  the  acid.  The  alkaloids 
do  the  same  thing.  Ex. :  H3  N  -}-  H  Cl  =•  H4  N  Cl.  Ammonium 
chloride  may  be  written,  H  NH  Cl;  chloride  of  ammonia,  so  C6H7N, 
HC1  =  chloride  of  aniline,  and  C17  H19  N  O3  H  Cl,  3  H2  O  —  chlo- 
ride (or  "hydrochlorate")  of  morphia  (with  water  of  crystallization). 
(For  fuller  account  of  each  alkaloid,  see  cyclopedia.) 

Morphia  (Cn  H19  N  O6,  H,  O),  or  morphine,  is  the  principal  alka- 
loid in  opium,  the  dried  juice  of  the  poppy.  In  small  doses  it  acts  as 
a  xedative;  in  large  doses,  as  a  narcotic  poison.  It  is  combined  with  me- 
conic  acid  in  the  plant  as  meconate  of  morphia.  A  salt  of  morphia, 
(sulphate  or  chloride,  usually)  is  sold  at  the  drug  stores  as  ' 'morphia," 
and  the  same  is  true  of  many  other  alkaloids.  Laudanum  is  tincture 
of  opium;  paregoric,  a  camphorated  tincture,  flavored  with  aromat- 
ics.  Many  patent  concoctions  for  "soothing"  children  contain  opium, 
and  are  very  pernicious. 

On i nia,  or  quinine  (C20  H24  N2  O2  3  H2  O),  is  obtained  from  the 
bark  of  the  cinchona,  a  tree  found  native  in  Peru.  It  is  largely  used 
in  medicine,  especially  in  feyers.  It  has  a  bitter  taste. 

Aeonitia,  or  aconite  (C54  H40  N  O2),  is  obtained  from  aconite  leaves 
and  root.  It  is  used  in  fevers  to  cause  perspiration  (sudorific).  It  is 
one  of  the  most  violent  poisons  known. 

Strychnia,  or  strychnine  (C21H^N.2O2)  is  the  alkaloid  in  mix  vomica 
(seeds)  and  the  St.  Ignatius  bean.  It  also  is  one  of  the  most  poison- 
ous of  the  alkaloids.  It  is  largely  used  in  medicine  as  a  nervous  tonic. 
It  is  intensely  bitter. 

Atropia  (C17  H.23  N  O3)  exists  in  belladonna,  or  Deadly  Nightshade, 
as  malate  of  atropia. 

Nicotia,  or  nicotine  (Cw  H14  N.J,  is  the  volatile  liquid  alkaloid  of 
the  tobacco  plant.  It  is  intensely  poisonous,  but  unfortunately,  being 
so  volatile,  its  smoke  does  not  kill.  The  human  system  at  length 
becomes  tolerant  of  the  presence  of  the  poison,  even  in  the  stomach. 

As  a  rule,  it  stupifies  and  clouds  the  intellect,  especially  of  persons 
not  full  grown.  Those  boys  who  are  great  smokers  rarely  take  a  high 
standing  in  their  classes. 

The  alkaloids  are  very  numerous,  as  are  also  the  vegetable  acids.  For 
tests  see  larger  text-books. 


DYEING.  127 


CHAPTER  XXXVI. 


DYEING. 

EXP.  145.  —  Dissolve  a  little  aniline  blue  (C20  H16  (C6H5)3N3)  in  alco- 
hol, and  dip  clean,  white  silk  thread  into  it.  Expose  the  thread  to  the 
air,  the  alcohol  evaporates  and  leaves  the  blue  color  adherent  to  every 
fiber  of  the  silk. 

Aniline  (C6H5  H2N)  is  a  volatile,  oily  liquid;  colorless,  when  pure, 
but  by  oxidation,  action  of  chemical  agent*,  etc.,  aniline  black,  red, 
(magenta),  orange,  yellow,  green,  blue,  and  violet  (mauve)  are  produced. 
The  reactions  in  the  formation  of  the  wonderful  "aniline  dyes"  are  by 
far  too  complex  for  introduction  here. 

EXP.  146.  —  Upon  fine  zinc  filings  in  a  beaker  place  a  minute  quantity 
of  blue  indigo,  add  a  moderately  strong  solution  of  potassium  hydrate 
(potash)  and  heat. 


(b)-H2    +    C1HHWN202    =    Clt;H12N202 

reducing  blue  indigo  white  indigo 

agent 

Dip  a  piece  of  clean,  white  woolen  (or  cotton)  cloth  in  the  solution 
of  white  indigo  and  expose  to  the  air,  blue  indigo  is  formed  in  its  fibers 
by  oxidation  and  adheres,  that  is,  is  a  "fast  "  color  (does  not  wash  out 
in  warm  soap-suds). 

C16H12N202    +    O     =    C^H^N.O,    -f    H20 

white  indigo  blue  indigo  evaporates 

EXP.    147.  —  Divide   a  dilute  (1   per  cent.)  solution  of  picric   acid 

(C6H3N3O10)  into  two  portions.  Into  one  dip  a  piece  of  woolen 
yarn,  into  the  other  dip  cotton  yarn.  Remove  each  and  wash.  The 
first  is  dyed  a  brilliant  yellow,  the  second  is  not  colored. 

Substances  that  dye  directly  are  called  substantive  colors.  Coloring 
substances  may  form  colored  compounds  with  the  fibers  of  the  cloth, 
or  (usually)  may  merely  adhere  to  the  fibers.  Cotton  and  linen  often 
require  different  treatment  from  wool  or  silk  to  produce  the  same  color, 
and,  in  general,  are  dyed  with  more  difficulty. 


128  CHEMICAL  PRIMER. 

EXP.  148. — Divide  a  solution  of  alum  into  two  parts.  To  the  first 
add  H4  N  H  O,  a  flocculent  precipitate  of  aluminum  hydrate  (A12  6  HO) 
falls.  To  the  second  acid  a  few  drops  of  solution  of  cochineal  (car>ii(i«- 
ink),  and  then  H4  N  H  O.  Al,  6  H  O  is  precipitated  as  before,  and 
slowly  settles,  carrying  all  the  coloring  matter  down  with  it,  forming  a 
"tofe." 

8ome  other  metallic  hydrates  (or  oxides),,  especially  of  tin  and  of 
iron,  have  the  same  great  affinity  for  organic  coloring  matter.  The 
compounds  they  form  with  coloring  matters  are  called  lakes.  The 
hydrates  also  have  "great  affinity  for"  (adherence  to)  the  fibers  of 
cloth.  Every  one  knows,  that,  though  "dirt"  can  be  readily  washed 
from  a  white  apron,  iron  rust  is  removed  with  great  difficulty  (only  In- 
chemical  agents — see  OXALIC  ACID).  Hydrates  (or  salts,  from  which  the 
hydrates  may  be  produced),  that  have  a  great  affinity  for  coloring  mut- 
ter and  also  for  the  fiber  of  cloth,  are  called  mordants,  and  a  color  that 
will  not  dye  directly,  but  needs  a  mordant,  is  called  an  adjective  color. 

Coloring  by  means  of  mordants  is  the  usual  method.  The  most 
common  mordants  are  copperas,  tin  salts,  and  alum.  The  cloth  is  first 
dipped  into  a  solution  of  the  mordant  and  then  into  the  dye.  Different 
mordants  produce  different  colors,  when  used  with  the  same  dye.  The 
mordants  may  be  applied  by  means  of  stamps  (or  rollers)  and  any  pat- 
tern (as  for  calico)  brought  out  in  the  various  colors. 

EXP.  149. — Boil  a  piece  of  Fe  S  O4  in  nitric  acid  (90  per  cent.),  till 
red  flumes  cease  to  appear;  dilute  and  filter.  Preserve  filtrate  (Fe.,3  SO+. 
"persulphate  of  iron  ").  Dip  clean  silk  into  this  ferric  sulphate  (mor- 
dant) and  leave  for  a  few  minutes.  Drain,  and  immerse  in  solution  of 
potassium  ferro-cyanide  (dye).  It  is  colored  a  deep  blue  (Prussian 
blue). 


2Fe,3SOi  -f  3K4Fe(CN)(;  =  6K,SO4  +  (Pe2)23Fe  (C  N)(i 

mordaut  dye  ferric  ferro  cyanide 

Prussian  Mm- 

The  reactions  of  the  organic  dyes  with  their  mordants  are  too  com- 
plex to  be  written  out.  Indeed,  many  of  them  are  unknown.  The 
most  common  coloring  substances  are  madder  (coloring  principle  aliza- 
rin, now  made  artificially  from  coal-tar),  cochineal  (dried  insects  from 
cactus  of  Central  America,  coloring  principle,  carmine),  logwood, 
indigo,  litmus,  etc.  (See  DYEING,  in  cyclopedia). 


OILS,  FATS,  RESINS,  KTC.  129 


CHAPTER  XXXVII. 


OILS,    FATS,    RESINS,    ETC. 

There  are  two  great  classes  of  oils:  Fixed  and  Volatile 
(or  Essential).  Fixed  oils  cannot  be  distilled  without 
decomposition  into  various  hydrocarbons.  Volatile  oils  can 
be  readily  distilled. 

Fixed  oils  are  salts  (using  the  term  in  a  wide  sense). 
Hard  fat  is  principally  glyceryl  stearate  ("  stearin"),  soft 
fat,  glyceryl  palmitate  ("palmitin"),  and  liquid  fat,  gly- 
ceryl oleate  ("olein").  Fixed  oils,  when  boiled  with  an 
alkali  (K,  Na,  etc,  hydrate),  react  with  the  alkali  to  form 
a  "soap,"  and  "glycerine."  (TABLE  No.  2). 

Exr.  150.  —  Mix  a  strong  solution  of  caustic  potash  (K  H  O)  with 
olive  oil  and  boil  for  about  twenty  minutes. 

3KHO  +  C3H53C18H330.   =   3KC18H33O2  -f  C3H53HO 

potassium  glyceryl  oleate  potassium  oleate  glyceryl  hydrate 

hydrate  (olive  oil)  (soft  soap,  because  it  is  a  (glycerine) 

("lye")  deliquescent  salt) 

Set  aside  to  cool,  the  .soap  and  glycerine  separate. 

Olive  oil  contains  some  glyceryl  palmitate,  so  that  the 
soap  is  partly  potassium  palmitate.  If  tallow  be  taken  in 
place  of  olive  oil,  the  soap  is  principally  potassium  stearate. 
Inspection  of  the  reaction  reveals  the  whole  story  of 
soap-making.  If  "caustic  soda"  is  taken  with  tallow,  the 
reaction  becomes 


caustic  soda  glyceryl  stearate  hard  soap  glycerine 

(not  deliquescent) 

Potassium  forms  a  soft  soap  and  sodium  a  hard  soap.  Ca 
forms  an  insoluble  "lime  soap."     M.g  also  forms  an  insol- 


130  CHEMICAL  PRIMES. 

uble  soap.  Insoluble  soaps  are  sometimes  used  in  medicine 
and  in  the  arts.  Solutions  of  soluble  soaps  (K  and  Na)  are 
good  solvents  of  the  cuticle  and  of  many  forms  of  "dirt," 
and  hence  are  valuable  cleansing  agents.  They  must  be 
used,  however,  with  soft  water.  If  soft  soap  (for  instance) 
is  put  into  hard  water  (i.  e.,  containing  Ca  S  O4,  or  other 
soluble  sulphate),  the  soap  is  destroyed,  and  an  insoluble 
''lime  soap"  formed  by  the  following  reaction:— 

CaSO,  +  2KC18HMO2    =    K.2SO4   +   Ca2C18HMO2 


insoluble  li 


A  similar  reaction  takes  place,  if  the  water  is  only  of 
temporary  hardness  (see  EXP.  33).  Water  of  temporary 
hardness,  as  we  have  seen,  is  softened  by  boiling.  Water 
of  permanent  hardness  may  be  softened  (for  washing  pur- 
poses) by  adding  borax  (Na,  B4  O7),  or  washing  soda 
(Na,  C  O3,  10  H2  O).  If  the  last, 

CaSO,  +  Na,C03  =  Na,  S  O4  +  Ca  C  O, 

cause  of  (remaining  in  solution  precipitate 

hardness  but  not  affecting 

the  soap) 

In  making  "lye"  from  wood  ashes,  the  ashes  are 
leached  in  a  large  tub  containing  "lime"  (Ca  2  H  O)  at  the 
bottom.  The  K,  C  O3  of  the  ashes  is  carried  by  the  hot 
water  down  through  lime,  and  the  reaction  is:— 

Ca2HO  +  K.CO,  =  2KHO  +  CaCO:i 

"lye" 

If  no  lime  is  used  of  course  the  lye  is  potassium  carbonate  (impure 
solution),  and  in  making  soap  from  K,  C  O3  we  have  (if  olive  oil  is 

used) 

3  K2  C  O3    +    3  H2  O    -f    2  C3  H5  3  C]8  H33  O2     = 

6KC18H3302    -f    2C3H53HO     +    SCO, 

M>ap 

Soap  usually  contains  an  excess  of  the  alkali.  Home-made  soap  con- 
tains both  alkali  and  glycerine  and  is  very  variable  in  its  composition, 
containing  several  fat  acids  united  to  the  alkali.  Soap  is  insoluble  in 
salt-water  and  hence  separates  if  salt  be  added  to  the  "suds." 


OILS,  FATS,  RESINS,  ETC.  131 

"  Stearin"  candles  are  made  (chiefly)  of  stearic  acid  by  decompos- 
ing the  tallow  by  superheated  (285P)  steam. 


+      C3H53C18Ha502  =  3HC18H35O2+     C3H53HO 

.stf.'iiii  tallow  stearieacid  glyceiine 

(stearin  candles)  t 

There  are  two  great  classes  of  fixed  oils,  drying  oils  and  non-drying 
oils.  A  drying  oil  (as  linseed  oil,  i.  e.,  flax-seei  oil),  when  exposed  to 
the  air,  oxidizes  to  a  hard  resinous  substance.  A  non-drying  oil  does 
not  oxidize  to  a  resinous  body  when  exposed  to  the  air,  but  instead 
suffers  a  fermentation  that  sets  the  acid  of  the  oil  free,  that  is,  the  oil 
becomes  "rancid."  For  instance,  the  purest  olive  oil  is  not  entirely 
free  from  nitrogenous  material,  and  fungus  germs,  creeping  in,  cause 
the  following  reaction  :  — 
Q,  H5  3  C,g  H33  O,  -f  3H20  =  3  H  G18  H.,3  O,  +  C3H,3HO 

olive  oil  moisture  oleic  acid  glycerine 

from  air 

As  we  have  seen,  glycerine  (C3H53HO)  is  a  "by- 
product" in  the  manufacture  of  soap.  Glycerine  is  classed 
by  chemists  as  an  alcohol.  It  is  a  viscid,  sweet  liquid,  a 
good  solvent  and  a  valuable  antiseptic.  Jt  is  useful  in 
dressing  wounds,  because  it  is  not  volatile,  but  protects 
from  the  air  and  keeps  the  part  moist.  Glycerine,  treated 
with  nitric  and  sulphuric  acids,  becomes  the  fearful  explos- 
ive nitro-  glycerine  (C3  H5  3  N  O3l  glyceryl  nitrate). 


Volatile  oils  (or  Essential  oils)  are  of  vegetable  origin. 
They  exist  in  the  petals  of  flowers,  in  leaves  (of  mint),  in 
seeds  (of  carraway).  in  rind  of  fruit  (of  orange,  lemon) 
and  in  the  root  (of  sassafras).  They  are  usually  obtained 
by  distilling  with  water  (passing  steam  over),  from  the 
part  of  the  plant  containing  them.  They  do  not  make 
soaps.  Their  "solution"  in  alcohol  is  called  an  essence. 
Adulteration  with  a  fixed  oil  is  easily  discovered  by  evap- 
orating on  white  paper  and  noticing  that  a  grease  spot  is 
left. 

Oil  of  Turpentine  (C10  H16  "spirits  of  turpentine")  is  obtained 
from  the  "pitch"  of  pines  by  distillation."     It  is  an  excellent  ftolrr.nt, 


132  CHEMICAL  PRIMER. 

dissolving  the  resins  to  form  varnishes.  A  large  class  of  volatile  oils 
are  pure  hydro-carbons,  many  having  the  same  empirical  formula  with 
oil  of  turpentine,  though  widely  different  in  properties. 

Of  a  second  class  Camphor  (CU1  H16  O)  is  a  type,  as  oil  of  bitter 
almonds,  fcinnamon,  spearmint,  etc.  These  all  contain  O. 

A  third  class  of  "strong  smelling'"  volatile  oils  contain  S.  Ex  :  Oil 
of  mustard,  horse-radish,  onion,  etc. 

A  resill  is  an  essential  oil  oxidized.  ("Rosin"  is  the  resin  of  "tur- 
pentine"). A  balsam  is  an  oleo-resin,  i.  e.,  a  resin  dissolved  in  a  volatile 
oil,  or  a  volatile  oil  partially  oxidized.  I£a  balsam  is  distilled,  the  essen- 
tial oil  passes  over,  leaving  the  resin  behind.  Shellac  is  a  resin 
obtained  from  lac,  the  juice  of  an  East  India  tree.  Amber  is  a  fossil 
resin. 

(J  inn  resins  are  milky  exudations  from  many  plants,  which  after- 
ward solidify  in  the  air.  Gutta-percha  is  obtained  from  the  juice  of 
an  East  India  tree,  as  is  also  gum-benzoin,  the  chief  source  of  beiizoic 
acid  (HCTH5O,)  India-rubber  (caoutchouc)  is  the  solidified  juice 
of  certain  tropical  trees.  Vulcanized  rubber  is  made  by  heating  the 
rubber  with  sulphur  ((loodyear's  patent). 


CHAPTER  XXXVIII. 


ANTIDOTES. 

When  a  person  is  taken  suddenly  and  violently  ill  after  eating  some- 
thin  g,  poisoning  may  be  suspected. 

A  poison  is  a  substance,  which,  if  introduced  into  the 
animal  system,  may  produce  morbid  or  deadly  effects.  We 
give  antidotes,  either  (1)  to  get  rid  of  the  poison  at  once 
(bv  means  of  an  emetic,  or  cathartic — a  mechanical  anti 
dote),  or  (2)  to  hinder  its  absorption  (as  when  we  give  a 
chemical  antidote  to  form  an  insoluble  compound  with  the 
poison:  see  EXP.  11),  or  (3)  to  counteract  its  effect  (as  when 
we  give  stimulants  for  the  poison  of  serpent  bites,  for  nar- 
cotic poisons,  etc.). 


ANTIDOTES.  133 


EXP.  151. — Shake  up  thoroughly  the  white  of  an  egg  in  a  bottle  half 
filled  with  water  and  filter.  The  filtrate  is  a  solution  of  albumen. 
Arrange  test  tubes  containing  very  slightly  ac'd  solution  of  soluble  salts 
of  Hg  (corrosive  sublimate),  Cu,TZn,  Sn,  Fe  (copperas),  Ag  (nitrate), 
Pb  and  As  respectively.  Into  each  let  fall  two  or  three  drops  of 
albumen  solution.  Insoluble  compounds  (of  albumen  and  the  metal, 
formula  too  complex  to  be  written)  are  precipitated. 

Albumen  (milk,  Hour  and  water,  and  especially  raw 
eggs)  is  an  excellent  chemical  antidote  for  metallic  salts. 
As  precipitates  are  not  absolutely  insoluble  in  the  stomach, 
they  should  be  immediately  removed  by  an  emetic. 

The  best  emetic  is  the  common  one,  "mustard"  (a  tea- 
spoon t'ul  in  a  cup  of — preferably  warm — water).  When- 
ever poisons  are  to  be  removed  by  an  emetic,  warm  water 
should  be  freely  drank  to  rinse  out  the  stomach  thor- 
oughly. Oils  (fats,  butter,  and  lard)  and  mucilaginous 
drinks  (as  flax-seed  tea)  are  always  beneficial,  both 
immediately  and  for  treatment  afterward.  In  general, 
whatever  would  be  good  treatment  for  a  burned,  bruised, 
or  injured  skin,  is  good  treatment  for  the  mucous  mem- 
brane of  the  alimentary  canal,  burned  and  irritated  by 
some  poison. 

If  silver  nitrate  or  corrosive  sublimate  are  quite  strong,  the  antidote 
must  be  given  within  a  few  seconds,  or  the  poison  will  have  done  its 
worst,  and  recovery,  if  it  takes  place  at  all,  must  depend  upon  after 
treatment.  A  rather  large  dose  of  a  mild  cathartic  (as  castor  oil)  is 
much  to  be  preferred  to  the  emetic  whenever  strong  solution  of  either 
sublimate  or  nitrate  has  been  taken.  The  best  antidote  for  silver 
nitrate  is  salt  and  water,  as  we  have  inferred  from  EXP.  5. 

If  the  other  metallic  salts  (except,  see  cyanides  below)  have  been 
swallowed,  especially  in  the  solid  state  (powder),  the  antidote  may  be 
given  later  (from  ten  to  twenty  minutes)  with  hope  of  its  doing  good. 
But  the  danger  rapidly  increases  with  tli"  lapse  of  time. 

Most  salts  of  Zn  and  Sb  (also  Cu  S  Oj  are  fortunately  emetics 
themselves,  but  if  vomiting  does  not  occur,  prompt  action  must  be 
resorted  to.  The  best  autidote  for  zinc,  copper,  or  iron  sulphate  is 
sodium  carbonate,  "washing  soda  "  (followed  by  emetic). 


134  CHEMICAL  PRIMER. 

ZnSO      -f     NaiC03     =     Na   S  O      -f     Zn  C  O 

insoluble 

The  best  antidote  for  arsenic  (or  Sb)  is  fresh,  moist  ferric  hydrate, 
Fe.j  6  H  O.  It  is  best  precipita^d  when  needed  (by  mixing  H  Cl 
solution  of  ferric  chloride  and  sodium  carbonate).  An.  insoluble  ferric 
arsenate  (Fe2  &  As  O4)  is  formed  in  the  stomach.  Chalk  and  oil 
mixed  may  be  given  to  envelop  the  particles  of  As  mechanically,  but 
the  thing  to  be  depended  upon  ordinarily  is  the  emetic. 

"Carefully  prepared  iron  filings  (Exp.  125)  is  a  good  antidote  for  cop- 
per compounds  (with  emetic)." — Attfield.  A  careful  dose  of  potassium 
ferrocyanide,  is  also  a  good  antidote,  as  Cu,,  Fe  (C  N)6  is  insoluble. 

Magnesium  sulphate  (Epsom  salt)  [Exp.  11]  is  the  best  antidote  for 
lead  and  barium  compounds  (\vith  emetic). 

Ammonium  carbonate  (small  dose  of  5  per  cent,  solution,  as  itself  is 
poisonous)  is  the  best  antidote  for  tin  compounds  (with  emetic). 

Example :  f 

Sn  C12  -f  (H4N),  C  05  -f  H,  O  =  2  H,  N  Cl  +  Sn  2  HO  +  C  O, 

precipitate 


The  antidote  for  acids  sulphuric,  nitric,  hydrochloric, 
etc.)  is  magnesium  carbonate  (see  Reaction,  class  4), 
chalk,  lime-water  or  soapsuds.  The  antidote  must  be  given 
within  a  few  seconds  if  the  acids  are  strong. 

For  oxalic  acid,  lime-water  (Exp.  14)  or  chalk  is  the  best  antidote. 
Prussic  acid  (K  C  N)  and  other  cyanides  require  stimulants,  as  cold 
douche  to  ille  spine,  dilute  ammonia  water  inhaled  and  ammonium  car- 
bonate given  in  small  d  '-^x  (see  snake  poison  below).  If  prussic  acid  is 
strong  there  is  no  antidote.  Give  no  emetics  with  acids  (unless 
acid  is  very  dilate),  but  administer  oil  freely  (olive). 


The  antidote  for  alkalies  (caustic  potash  ("lye"),  caustic 
soda,  etc.)  is  a  dilute  acid,  preferably  the  most  common  one 
vinegar  (acetic). 

KHO    +    HC.2H:(0.,     =    KC,  H3O,    -f    H,  O 

•  soluble  but 
harmless  salt 

Or  tartaric  acid,  "cream  of  tartar,"  citric  acid  (lemon  juice)  etc.  (If 
these  are  not  at  hand  and  the  mineral  acids  are  given,  the  acid  must  be 
very  dilute  and  given  sparingly.  A  n  overdo*'  would  he  substituting  one 
poison  for  another}. 


ANTIDOTES.  135 

If  the  caustic  alkalies  are  strong,  the  antidote  must  follow  in  a  few 
seconds,  or  it  will  be  of  no  avail.    Give  no  emetic  with  alkalies, 

(unless  they  are  very  dilute,  and  no  other  remedies  as  the  above,  or  oil, 
can  be  had). 


For  narcotic  poisons  (as  opium,  morphine,  cholera 
medicines,  : 'soothing  syrups"),  and  the  alkaloids  in  gen- 
eral, the  emetic  is  to  be  relied  upon  chiefly,  though 
tannic  acid  (strong  tea  or  coffee)  may  be  given,  as  it  forms 
an  insoluble  compound  with  many  alkaloids. 

The  narcotic  poisons  require  in  addition  to  the  emetic,  stimulants 
(strong  coffee,  brandy,  ammonium  carbonate — avoid  overdose  of  latter, 
see  below)  and  vigorous  efforts  to  keep  the  patient  awake.  Aconite  calls 
for  stimulants.  Strychnine  requires  above  all  the  emetic,  also  the  inhala- 
tion of  chloroform  or  ether  to  check  spasms.  Patient  must  be  kept  as 
quiet  as  possible. 

The  emetic  should  be  promptly  given  in  case  of  poisoning  by 
unhealthy  fish  or  meat.  Oils  should  follow  (and  paregoric  in 
severe  cases). 

Phosphorus  poisoning  requires  the  emetic  and  mucilaginous 
drinks  with  magnesium  hydrate,  followed  by  large  doses  of  the  cathar- 
tic (purgative)  castor  oil. 

It  is  not  generally  known  that  carbolic  acid  is  a  more  dangerous 
poison  than  strychnine.  Strichnine  kills  "deliberately"  and  with  a 
smaller  dose,  but  carbolic  acid  does  its  work  quick.  Strychnine  gives 
time  (10  to  30  mimites)  to  hunt  up  antidotes,  or  call  a  physician;  but  if 
a  teaspoonful  of  strong  carbolic  acid  is  taken,  usually  no  remedy  will 
save  life  after  thirty  seconds  have  elapsed.  As  it  is  frequently  used  in 
sick  rooms  for  bathing  purposes  (diluted),  its  well  known  odor  is  no 
protection  in  such  cases.  Olive  oil  (butter,  lard,  etc. )  freely  given, 
followed  by  castor  oil  (cathartic)  is  its  best  antidote.  Give  no 
emetic. 

For  the  bite  of  poisonous  serpents  (poison,  a  powerful  sedative), 
stimulants,  as  alcoholic  liquors,  but  best  of  all,  ammonium  car- 
bonate (a  teaspoonful  of  10  per  cent,  solution,  which  may  be  carried 
in  small  vial,  tightly  corked,  in  the  vest  pocket)  should  be  taken 
within  a  few  second*.  The  dose  of  ammonium  carbonate  should  be 


136  CHEMICAL   PRIMER. 


repeated  twice  at  intervals  of  ten  minutes.  If  possible,  the  wound 
should  be  immediately  cauterized  (by  nitric  acid,  caustic  potash,  etc.), 
or  a  ligature  put  about  the  limb  above,  and  the  poison  sucked  out  from 
the  wound  (the  poison  is  harmless  in  the  stomach). 

The  pupil  will  notice,  that  in  most  cases  of  poisoning,  the  emetic  is 
given.  He  should  charge  his  memory  with  the  few  exceptions  [moder- 
ately strong  acids,  alkalies  (also  silver  nitrate,  corrosive  sublimate)  and 
carbolic  acid],  and  give  emetics  in  all  other  cases.  A  physician  should 
be  called  in  all  cases  of  serious  poisoning  to  direct  the  after-treatment. 

Poisons  should  never  be  left  within  the  reach  of  children. 
They  should  be  kept  by  themselves,  apart  from  non-poison- 
ous medicines.  They  should  be  kept  plainly  labeled  as 
poisons,  and  any  substance  in  an  unlabeled  bottle  should 
be  promptly  destroyed.  Whenever  a  poison  is  bought,  its 
antidote  should  be  bought,  placed  beside  it  and  plainly 
labeled.  After  this  is  done,  it  should  be  remembered  that 
"an  ounce  of  prevention  is  worth  a  hundred  pounds  of 

cure." 

MISCELLANEOUS    QUESTION  S. 

1.  Tell  what  you  know  of  S  O.,  (3  lines). 

2.  Tell  what  you  know  of  H.^  S. 

3.  What  is  glass  ?     How  annealed  ? 

4.  How  might  you  tell  whether,  or  not,  a  white  powder  was  As^O:1 '! 

5.  Give  Marsh's  test  for  "arsenic."     How  told  from  antimony  ? 

6.  What  is  an  alloy?  amalgam?  metal? 

7.  What  three  methods  of  "mining  for  gold  ?"  and  tell  much  more 
about  each  than  you  find  in  this  Primer  (20  lines). 

8.  For  what  is  platinum  used  ? 

9.  What  would  you  do,  if  you  had  taken  by  mistake  nitrate  of  Ag  ? 

10.  How  would  you  test  for  corrosive  sublimate  (Hg  C12)  ? 

1 1 .  Why  can  some  metals  be  cast,  while  others  can  not  ? 

12.  What  is  "white  lead,"  and  how  made? 

1 3.  What  is  the  antidote  for  lead  acetate  ? 

14.  Give  Bessemer 's  process  for  making  steel. 

15.  What  is  "galvanized  iron?"  "tinware?" 

16.  What  is  fusible  metal  ? 

17.  Difference  between  water-slacked  and  air-slacked  lime  ? 

18.  Give  reaction  in  making  soft  soap  (use  TABLE). 

19.  How  is  brown  sugar  refined  ? 

20.  Reactions  in  alcoholic  and  acetic  fermentations  (CoH^O,;  sugar). 

21.  Why  is  soap  wasted  when  hard  water  is  used  in  washing? 

22.  What  is  rosin  ?  a  resin  ?  balsam  ?  tincture  ? 

23.  What  would  you  do,  if  one  had  taken  an  overdose  of  morphine  ? 

24.  In  what  cases  of  poisoning  should  no  emetic  be  given  ? 

25.  What  makes  the  bread  "rise?"     Explain  fully. 


ADDITIONAL  EXPERIMENTS.  137 


APPENDIX. 


ADDITIONAL    EXPERIMENTS. 

EXP.  1.— Repeat  EXP.  30  with  a  test  tube  of  the  right  size  and  the 
H  flame  "siugs."  It  sets  the  column  of  air  in  vibration  within  the 
test  tube. 

EXP.  2. — Ignite  a  small  jet  of  H  by  holding  in  it  platinum  sponge 
[previously  heated  to  expel  absorbed  gases  which  (especially  ammonia) 
hinder  the  action]. 

EXP.  3. — Place  a  sounding  tuning-fork  in  a  jar  of  H;  the  tone  is 
raised  to  a  shrill  pitch. 

EXP.  4. — Burn  a  minute  jet  of  O  (driven  by  reservoir  (1)  from  holder 
(3)  as  in  frontispiece)  in  a  jar  of  H,  quickly  igniting  the  jet  by  pass- 
ing through  burning  H  at  the  mouth.  (See  note  EXP.  25). 

EXP.  5. — Connect  H  and  O  holders  with  oxy-hydrogen  blowpipe, 
and  igniting  the  H  first,  turn  on  the  O.  Place  small  piece  of  fine  Pt 
wire  (fused  into  glass  holder)  in  the  flame.  It  melts.  [The  rubber  cork 
in  the  H  holder  should  be  well  oiled  and  firmly  bound  down  by  strong 
twine  fastened  to  shoulder  of  the  bottle.  The  H  should  be  drawn  into 
a  test  tube  over  water  and  tested  before  it  is  burned  in  the  blowpipe. 
If  it  burns  quietly  after  taking  fire  it  is  safe  to  ignite  jet.  If  it  burns 
explosively,  it  is  mixed  with  air  and  must  not  be  ignited.  The  holder 
is  first  filled  completely  with  water  and  the  H  or  O  (from  generator  as 
frontispiece  2)  pressed  backward  expelling  the  water,  the  reservoir 
being  kept  so  that  the  water  in  it  shall  be  only  about  a  decimeter  above 
the  water  in  the  holder]. 

EXP.  6. — Into  a  tube  closed  at  one  end  (through  which  Pt  wires  are 
fused)  filled  and  inverted  over  mercury,  put  2  cu.  cm.  of  O  and  4  cu. 
cm.  of  H  %nd  explode  by  electric  current.  The  mercury  rises  and  with 
the  water  above  completely  fills  the  tube  (except  perhaps  a  bubble  of 
gas,  which  is  the  result  of  inaccurate  measurement).  Composition 
of  water  is  proved  by  synthesis,  as  nothing  is  found  dissolved  in  the 
water. 

10 


138   '  CHEMICAL  PRIMER. 

EXP.  7. — Mix  in  the  dark,  dry  Cl  and  dry  H  in  a  stout  bottle,  and 
with  care  explode  by  sudden  exposing  to  direct  sunshine.  H  Cl  fumes  are 
formed. 

EXP.  8. — In  a  flask  place  a  few  minute  pieces  of  P  and  cover  with 
strong  solution  of  caustic  potash.  Displace  the  air  in  the  flask  by 
passing  H  through  the  stopple  of  flask  until  the  bubbles  caught  over 
pneumatic  tub  burn  quietly.  Close  by  wire  spring  the  rubber  tube 
through  which  H  is  admitted  arid  heat  flask. 

3KHO     -f    P,    -f    3H20     =    3KH.P02    -f    H:,  P 

The  hydrogen  phosphide  (phosphine)  takes  fire  because  vapor  of  liquid 
P2  H4  is  present  and  the  beautiful  white  rings  of  smoke  ascend.  Pure 
H3  P  is  not  spontaneously  inflammable.  Remove  heat  and  pass  H  as 
before  and  throw  away  poisonous  liquid. 

CAUTION. — Perform  in  well  ventilated  room  (better  in  open  air)  and 
immediately  open  doors  and  windows  after  the  Exp. 

EXP.  9.- — The  best  test  for  the  element  P  (paste,  rat  poison)  is  that 
of  distillation.  Add  dilute  sulphuric  acid  and  pass  vapor  through  a 
condenser  (made  of  glass)  in  a  perfectly  dark  room  (and  into  water). 
The  vapor  is  distinctly  phosphorescent  if  even  a  minute  quantity  of 
free  P  is  present.  In  cases  of  poisoning  this  test  must  be  applied  with- 
out long  exposure  to  air,  as  P  in  presence  of  organic  matter  and  air 
rapidly  oxidizes. 

Exr.  10. — Heat  to  dull  redness  on  platinum  foil,  bread  containing 
alum,  boil  residue  in  dilute  H  Cl,  filter,  neutralize  with  ammonium 
hydrate;  a  flocculent  precipitate  of  Ala  6  H  O  falls. 

EXP.  11. — Heat  in  oxy -hydrogen  blowpipe  the  sharpened  end  of  a 
stick  of  quicklime,  a  dazzling  light  is  emitted  ("  lime  light ").  (Do  not 
look  directly  at  the  light). 

EXP.  12. — Add  a  small  quantity  of  albumen  (Exp.  151)  to  distille^ 
water,  or  to  animal  secretion  filtered.  Upon  pure,  colorless,  nitric 
acid,  in  test  tube  of  small  diameter,  slightly  inclined,  allow  the  liquid 
to  trickle  from  a  pipette.  A  sharp,  Avhite  zone  appears  at  the  junction 
of  the  two  liquids,  not  dissipated  by  heat.  This  is  an  excellent  test 
for  albumen.  (Urates,  if  present  in  excess,  produce  a  somewhat  similar 
white  zone,  but  the  zone  is  dissipated  by  heat  much  less  than  the  boil- 
ing point.  Be  careful  not  to  mistake  the  mere  mixing  of  the  zone  by 
boiling,  for  dissipation). 


ADDITIONAL  EXPERIMENTS.  139 

Ex  P.  13. — Add  to  animal  secretion  containing  albumen,  a  few  drops 
of  strong  caustic  potash,  and  filter.  Add  nitric  acid  to  distinct  acid 
reaction  and  boil,  White  coagula  appear  (greenish,  if  bile  is  present, 
brownish-red,  if  blood  is  present).  A  good  test  for  albumeii. 

EXP.  14. — Repeat  sugar  test,  EXP.  139.  Albumen,  if  present,  must 
be  removed  by  boiling  and  filtering.  Earthy  phosphates  should  be 
removed  by  adding  caustic  potash  to  alkaline  reaction  and  filtering. 
The  caustic  potash  used  must  have  been  kept  in  the  best  Bohemian 
glass  bottles,  and  not  in  bottles  containing  lead ;  otherwise  Pb  O  falls 
and  is  mistaken  for  Cu2  O.  A  mere  yellow  color  is  not  sufficient, 
there  must  be  an  actual  precipitate,  without  prolonged  boiling. — Perform 
the  same  experiment  without  heating,  lout  set  test  tube  away  for  twelve 
hours  instead.  The  Cu2  O  is  precipitated. 

EXP.  15. — Fill  a  test  tube  entirely  full  of  clear  animal  secretion  con- 
taining sugar ;  add  a  small  quantity  of  yeast  and  close  the  mouth  of 
the  test  tube  by  a  rubber  cork,  through  which  runs  a  fine  glass  tube 
half  way  to  the  bottom  of  the  test  tube.  Set  in  a  warm  place  for  ten 
or  twelve  hours.  The  C  O2,  produced  by  the  fermentation,  collects 
in  the  top  of  the  test  tube,  and  forces  the  liquid  out  of  the  fine  glass 
tube.  This  Fermentation  Test  is  an  excellent  one  for  sugar  in  animal 
secretions. 

EXP.  16. — Take  the  sp.  gr.  of  a  liquid  containing  sugar  before  fer- 
mentation and  after ;  every  "degree"  lost  corresponds  to  the  presence 
of  21  mgs.  of  sugar  in  10  cu.  cm.  of  the  liquid  (1  grain  of  sugar  per  fluid 
ounce).  That  is,  if  urinometer  shows  1050  before  and  1030  after  fer- 
mentation, there  are  420  mgs.  of  sugar  in  10  cu.  cm.  of  the  liquid  (or 
20  grains  per  fluid  ounce).  This  is  an  excellent  quantitative  test. 

EXP.  17. — Precipitate  a  large  amount  of  albumen  from  solution  in 
distilled  water,  by  adding  nitric  acid  and  boiling.  Filter,  wash  precip- 
itate, and  carefully  dry.  Arrange  a  dozen  narrow,  deep  test  tubes 
nearly  filled  with  water.  Carefully  weigh  out,  by  means  of  a  fine  pair 

of  scales  (any  chemist  will  allow  the  use  of  his  scales),  5,  10,  15 

55,  60  mgs.  of  albumen  powder,  and  placing  in  each  test  tube  respect- 
ively, allow  three  hours  for  settling.  By  means  of  &  very  fine,  sharp 
file,  carefully  mark  the  height  of  the  precipitated  albumen.  Reserve 
test  tubes  for  quantitative  testing  for  albumen.  (Phosphate  should 
first  be  removed  from  animal  secretions  by  alkali  and  filtration).  For 
example:  If  5  cu.  cm.  of  liquid  to  be  tested  were  placed  in  first  test 
tube,  and  the  precipitated  albumen  reaches  to  the  mark  on  the  test 
tube;  1  mg.  of  albumeii  is  present  in  every  cu.  cm.  of  the  liquid. 
This  is  a  very  convenient  quantitative  test  for  albumen. 


Quantitative  Test  for  Carbonic   Oxide  in   Schoolroom*  ;a*  an 
index  of  the  amount  of  poisonous  "  animal  vapor''  present.) 

The  proportion  of  carbonic  oxide  is  generally  estimated  by  volume  and  on  a  scale  of 
so  many  parts  in  10,000  of  air.  In  pure  out-door  air  there  are  about  4  parts  of  carbonic 
oxide  in  10,000  of  air.  ^  In  the  schoolroom  the  proportion  should  never  rise  above  8 
parts.  Examir.ation  of  the  following  reactions  and  explanations  will  reveal  the  sim- 
plicity of  the  test. 

C,  O,.  2  U>  O  =  Ba  C,  O4  -f-  4  H2  O. 


-f-H, 


Ba  2  H  O 

bariuin 

hydrate. 

171 

Ba  2  H  O 

171 


rystalized  barium 

oxalic  acid.  oxalate. 

126 

4-    C  Oa    =    Ba  C  03,    +    H2  O 

In  neutralizing  power . 

126  gms  of  cr.  oxalic  acid     =     171  gms  of  barium  hydrate. 
44gms  cf  C  O2  =     171     " 

therefore  44  gms  of  C  O.2      —     126     "     of  cr.  oxalic  acid. 
1  grm  C  O2  —  2.863  -j-  gms,  or  2863  mgs  of  cr.  ox.  acid. 

If  we  weigh  carefully  2863  mgs  of  cr.  oxalic  acid  (not  deliquesced)  and  dissolve  in 
1000  cu.  cm.  (litre)  of  water,  then  1  cu.  )cm.  of  that  u  standard  "  solution  will  equal 
(in  neutralizing  power)  1  millegram  of  carbonic  oxide.  [Keep  solution  in  dark  bottle.] 

We  then  make  a  solution  of  barium  hydrate  dissolving  about  5  gms  in  a  litre  of  water. 

Suppose  a  jug  (bottle)  with  tight  fitting  rubber  ark  holds  4155  cu.  cm.  (carefully 
measured),  which  jug  we  fill  from  the  air  of  the  schoolro»m  by  means  of  a  small  bel- 
lows (blown  a  sufficient  number  of  times,  say  25),  and  take  temperature  of  the  room 
at  the  same  time  as  20°.  Into  this  we  pour  from  a  sp.  gr.  bottle  (hol.iing  with  the 
glass  stopple  in,  100  cu.  cm.)  100  cu.  cm.  of  the  barium  hydrate  solution  and  shake 
thoroughly  at  intervals.  We  now  fill  the  burette  (frontispiece  5)  with  the  "  standard" 
solution  of  oxalic  acid,  to  a  point  a  little  above  0  and  run  it  down  carefully  drop  by 
drop  to  the  0  point  precisely.  Measuring  from  barium  hydrate  solution  (by  means 
of  another  sp.  gr.  bottle  holding  50  cu.  cna.)  50  cu.  cm.  we  pour  it  into  a  clean, 
wide-mouthed  bottle  and  add  a  little  blue  litmus  solution.  We  now  open  the 
burette  and  allow  the  acid  to  run  slowly  (the  last  drop  by  drov)  into  the  wide- 
mouthed  bottle  containing  the  50  cu.  cm.  of  barium  hydrate  solution.  It  takes 
say  24.5  cu.  cm.  of  acid  to  neutralize  the  alkali — (when  the  last  drop  needed  is  added 
the  litmus  suddenly  turns  red).  Now  carefully  fill  the  second  sp.  gr.  boitle  (previously 
carefully  rinsed  in  distilled  water)  with  the  solution  taken  from  the  jug  containing  the 
schoolroom  air  (but  this  solution  sh  uld  previously  have  been  poured  into  a  bottle  just 
big  enough  to  hold  it,  excluded  from  the  air  by  stopple  and  poured  off  carefully  after 
it  has  completely  settled.  This  excludes  the  barium  carbonate,  a  very  necessary  thing 
in  the  te.vt.)  Again  fill  the  burette  as  before  and  see  how  many  ou.  cm.  of  the  acid  are 
required  to  neutralize  the  50  cu.  cm.  taken  from  the  jug.  We  find  in  every  case  it 
requires  less,  because  the  carbonic  oxide  in  the  jug  has  already  neutralized  part  of  it. 
It  requires,  say,  22  cu.  cm.  of  the  acH.  24.5  cu.  cm. — 22  cu.  cm. =2.5  cu.  cm.  But 
from  equations  above  we  know  that  1  cu.  cm.  of  the  acid  corresponds  to  1  mg.  of 
carbonic  oxide  ;  therefore  as  we  poured  out  only  one-half  of  the  alkali  to  test  there 
were  5  rr-gs.  of  carbonic  ox'de  in  the  jug.  From  table  we  see  that  1  mg.  of  carbonic 
oxide  at  20°  occupies  .544470  cu.  cm.  of  space,  therefore  5  mgs.  occupy  2.72235  cu.  cm. 
The  question  then  becomes, — If  in  4055  (4155-100)  cu.  cm.  air  there  are  2.72235  cu. 
cm.  of  carbonic  oxide,  how  much  carbonic  oxide  in  10COO  cu.  cm.  of  air?  We  have  the 
proportion  4O55:  1OOOO::  «.7£2!t5:  - 

from  which  we  obtain  6.7  parts  in  10000  as  the  answer,  that  is  the  room  is  fairly 
ventilated. 

Space  occupied  by  1  mg.  o/C  Os  at  different  temperatures  (barom.  760  mm.) 


Degree. 

Degree 

Cubic  Cm. 

Degree. 

Degree. 

Cubic  Cm. 

Degree. 

Degree. 

Cubic  Cm. 

c 

p 

c 

F 

F 

0 

32 

.50'306 

21 

69.8 

.546328 

82.4 

.559336 

la 

59 

.535178 

22 

71.6 

.548186 

29 

84.2 

.561194 

16 

60.8 

.537037 

23 

73.4 

.550044 

30 

86. 

.563052 

17 

62.6 

.538895 

24 

75.2 

.551903 

31 

87.8 

.564910 

18 

64.4 

.540753 

2,i 

77. 

.553761 

32 

89.6 

.560769 

19 

66.2 

.542611 

26 

78.8 

.5?5619 

S3 

91.4 

.568627 

20 

68 

.544470 

27 

80.6 

.557477 

34 

93.2 

.570485 

35 

95. 

.572343 

A  factor  can  be  worked  out  for  Kach  jug  used  and  for  each  temperature,  so  that  by 
a  simple  multiplication  of  the  difference  shown  by  the  burette  the  result  i-  obtained. 
Any  bright  pupil  can  master  the  test  in  a  few  hours  and  can  apply  it  in  a  few  minutes 
by  using  factors.  The  test  can  be  made  after  school  or  before  school  the  next  day. 
Such  tests  regularly  report  d  would  do  much  to  awaken  an  interest  in  having  a  proper 
system  of  ventilation.  Abominable  is  too  tame  a  word  to  use  for  the  ventilation 
"enjoyed"  by  many  schoolrooms. 


METRIC  SYSTEM— TABLE  2  (con.) 


141 


METRIC   SYSTEM. 


LINEAR 


10  Millimetres  (mm. )  =  1  Centimetre  (em.)  j  10  Millilitre:* 

10  Centimetres  =  1  Decimetre  (dcm)  10  Centilitres 

10  Decimetres  =  1  METRE  10  Decilitres 

10  Metres  =  1  Dekametre  10  LITRES 

10  Dekametres  =  1  Hektometre  10  Dekalitres 

10  Hektometres          =  1  Kilometre  10  Hektolitres 


WEIGHTS. 
10  Milligrams  (mg.)  = 
10  Centigrams           = 
10  Decigrams 
1Q  Grams                    = 
10  Dekagrams           = 
10  Hektograms          = 

1  Centigram 
1  Decigram  (dcg.) 
1  GRAM  («m.) 
1  Dekagram 
1  Hektogram 
1  Kilogram  (kgm.) 

1  Metre  (meter) 
1  Litre             = 
1  Litre 
1  Gram             = 
1  Gram 

1  Kilogram      = 
1  Kilogram      = 

CAPACITY. 

=  1  Centilitre 
=  1  Decilitre 
=  1  LITRE 
=  1  Dekalitre 
=  1  Hektolitre 
=  1  Kilolitre 

39.37  inches. 


=  61  cubie  inches 
1  cu.  decimetre 
15.43  grains 
=  weight  of  1  cu.  cm.  of 

water  (4°) 
=  2  1-5  Ibs. 

=  weight  of  1  cu.  dcm.(litre) 
of  water  (4°) 


REFERENCE  TABLE  No.  2— CONTINUED. 
NEGATIVE  GROUPINGS. 


PO3     =     metaphosphate 
C5  H9  65     =     valerianate 
j  C  N  O     =     cyanate 

C  H  O2     =    formate 
C4H702  =  butyrate  (butter) 
C7  H5  02     =     berizoate 
[NO,     =     nitrite 


fc3H4O3     = 


J± 


lactate 
4  O3     =    urate 


73  J  B407    =    tetraborate  (borax) 
>,  I  MiiO4      =     manganate 
"   |  Mn2  O8     =     permanganate 
1  Cr2  O7     =:     bichromate 


C4H305     =     malate 


v-x^  •*-*-3  ^5         "      *         •**«••*•»%?  JS     / 

C7  H  07  =  meconate  (opium)      £  j  Fe  (C  N)0    =     ferrocyanidt 
C7  H3  O5     =    gallate  g  <• 


CA«T  Hi 


=     tannate 


Fe2  (C  N)12    =    ferridcyanide 


(         roan 
JH,N     - 


POSITIVE  GROUPING. 


amidogen 


142 


CHEMICAL  PRIMER. 


I. 


ADD  H  Cl. .  .  FILTER. 


Precipitate insoluble  chlorides 

Hg2  Cl2(ous)  Ag  Cl  and  Pb  C12. 
Wash,  boil  thoroughly  and  filter. 


Filtrate,  .soluble 
chlorides  of  other 
metals,  as — As,  Sb, 
Sn,  Cu,  Fe,  etc.  and 
also  of  Hg  (ic). 


Precipitate. . .  .Hg2  C12  and  Ag  Cl 

Wash  with  hot  water  and  add  warm 

H4  N  HO  (Ag  Cl  dissolves) 


Precipitate 
H2NHg2Cl,    amido 
mercurous  chloride, 

black. 

Add  two  or  three 
drops  aqua  regia.  Di- 
lute with  ten  drops 
of  water,  and  evap- 
orate filtrate  nearly 
to  dryness  at  low  heat. 
(Water-bath  is  best.) 
Again  dilute  with  20 
drops  of  water,  and 
filter.  Test  as  in  Ex. 
121. 


Filtrate..  Pb  Cl, 
Divide  into  three  portions 
and  to  the 


Filtrate..  AgCl. 
Add  HN03  to  acid  re- 
action. Ag  Cl  is  re- 
precipitated  because 
its  solvent  is  neutral- 
ized. Wash,  and  fuse 
on  charcoal  with  a 
little  K2CO3 
K,CO3-j-2AgCl  — 
Ag2C03  -f  2KC1 
S 
Ag2C03=Ag20-hC02 

2  Ag2  O  +  C  = 
0  O2   -{-    Ag4,   silver 
globule. 

No  incrustation  on 
charcoal  as  in  lead 
reaction. 


1st  add  H2  S  04 

PbCl2  4-  H2S04  = 
PbS04    +    2HC1 

white  precipitate 


2d  add  K2  Cra  07 


bichromate 

2PbCr04+2KCl  +  2HCl 

:hrome  yellow 
precipitate 


II.      Pass  H2  S  gas  thro'  filtrate  from  First  Group. 


Precipitate .  Cu  Hg(ic)  Pb  Bi  As 

Sb  Sn  (Au  Pt).    Collect,'wash, 

Digest  in  (H4  N)^ 

Precipitate 
Cu  Hg  (ic)  Pb  Bi. 
sh,  boil  in  HNO3,  filter 


Filtrate 
Soluble  sulphides  of 

other  metals. 

f Filtrate . .  As  Sb  SrT(AuPt) 
I  Add    dilute    H  Cl,  filter, 


Wash, 


,  add  strong  HC1 
1  boil,  dilute  slightly,  filter. 


3d  add  (H4  N)s  S 

PbCl2  4-  (H4N)2S  = 
PbS    4-    2(H4NCl) 

brownish  black 
pre'cipitate 


Fuse  with  little  K2  C  03  on 
charcoal. 

K2C03-j-PbSi=  PbC03+K2vS 
Pb  C  03  =   Pb  0  +  C  O2 

2PbO  +  C  =  CO,  +Pba 
(lead  globule,  malleable).  Bi  and 
Sb  are  brittle.  Heat  globule  in 
>xidizing  flame  of  blow-pipe  ;  a 
yellow  incrustation  (Pb  O)  appears 
upon  the  charcoal. 


a 

(ic). 

Black. 

Confirm 

by 
EXP.  121 

in 

original 
filtrate. 


Filtrate 

Cu  Pb  Bi 

Add  H4  N  H  O, 


filter. 


Ppt, 

As. 

I  Yellow. 
-  Confirm 


Filtrate.. Sn  Sb. 

Pour  into  H-apparatus,  and  obtain 
antimoriial  spot,  Exi'.  113. 


Precipitate  PbBi 

Wash,  add  a  few 

drops  H  N  O3 

dilute,  filter. 


Ppt.  Bi. 
Fuse  on 
charcoal 

with 
K2  C  03 
Brittle 
globule. 


Filt.   Pb 
Dilute, 

add 

H2  S  O4 

set  aside 

White 

ppt. 


Filtrate1      by  s» 

(ju      jExp.  Ill       remains  on  Zn. 

Dissolve  in   hot  HC1  Sb  (spot). 

dilute,  add   H2  S  ;   a   Test  as  in  Kxr.  113. 
brown   ppt.   of  Sn  S 
falls. 


in  EXP. 
125,  j 
after 

adding 

a  drop 
of 

sulph- 
uric 
acid. 


Auand  Pt  rarely  occur  in  solution.     Au 

may  be  tested  for  as  in  EXP.  115. 

Ammonium  chloride  gives  a  yellow,  crystal- 

line  precipitate  with  solution  of  Pt  C14. 


ANALYTICAL  C 


143 


111. 


To  Filtrate  from  Second  Group  add  H4  N  H  0  and  (H4  N').2  S. 
Warm  gently  and  filter. 


Precipitate.  .Co  Ni  Fe  Mn  Cr  Zn  Al 
Warm  gently  in  dilute  (5  per  cent.)  HC1. 


Filtrate.   Soluble  com- 
pounds of  other  metals. 


Precipitate.  .Co  Ni 


Fuse  a  portion  in 

borax  bead. 
Blue  color  indi- 
cates Co. 


Add  three  drops 


aqua  regia  to  re- 
maining portion,     precipitate 
and  evaporate  to      pe  Mn  Cr 
dryness.     Warm      ;puse  wjth 
with  few  drops  of        minute 
Co  C12,  and  dry|    quantity  of 
on  white  paper,      potassium 
Green  color       carbonate  and 

shows  Ni.       j       nitrate. 
Deep  green  indicates  Mn  (potassium  manganate). 
Boil,  filter. 


Filtrate  Fe  Mn  Cr  Zn  Al. 
Evaporate  nearly  to  dryness;  add 
Na  HO,  and  boil,  filter. 


Precipitate.  .Fe 
Add  tannic  acid,  and 
boil;  brownish-black 

solution  —  Fe. 


Filtrate..  Cr 

Add  acetic  acid,  boil 

violently;  add  lead 

acetate. 

Chrome-yellow  ppt. 
indicates  Cr. 


Filtrate..  Zn  Al 

Add  H2  S  in  excess, 

filter. 


Slaty 
white. 


Filtrate 

Al 
AddHCl 

to  acid 
reaction,  boil,  filter, 
and  to  filtrate  add 
ammonium  hydrate 
to  alkaline  reaction. 
A  flocculent  precipi- 
tate indicates  Al  ( Al- 
uminum hydrate). 


IV. 

To  Filtrate  from  Third  Group  and  H4  NH  0,  H4  N  Cl  and  (H4  N)2CO:i. 


Precipitate.  .Ba  Sr  Ca. 
Boil  in  little  dilute  H  Cl,  and  filter. 
Ba  (alone)  gives  green  by  EXP.  131. 
Sr,  by  same  method,  red;  and  if 
neither  color  is  seen,  Ca  alone  gave 
the  precipitate  of  this  group.  (If 
all  three  are  present,  they  are  sep- 
arated with  some  difficulty.) 


Filtrate 

Soluble  compounds  of  metals  of 
the  fifth  group. 


To  Filtrate  from  Fourth  Group  add  H4  N  H  O  to  alkaline  reaction  and 
thenHNa2P04.     Filter. 


A  crystalline  precipitate  of 
N  H4  Mg  P  04  indicates  Mg. 

In  filtrate,  test  for  Na  and  K 
flame  color. 

by 

BART  MORGAN  &  CO 


Market  Street  Station,  Oakland,  Cal. 

Will  furnish  the  following  set  of  Chemicals  (securely  bottled  and 
carefully  labelled)  and  Apparatus  on  receipt  of  thirteen  dollars  and 
fifty  cents  ($13.50),  or  omitting  the  articles  marked  with  a  star  (*)  will 
furnish  the  balance  for  eleven  dollars  ($11.00).  The  set  is  sufficient 
for  the  performance  (with  few  exceptions)  of  all  the  experiments  found 
in  this  Chemical  Primer. 


CHEMICALS. 


Acetic  Acid 8  grms. 

Alcohol 1  litre. 

Alum 8  grins. 

Ammonia  water 100    " 

Ammonium  chloride 4    " 

"          carbonate 10    " 

Anilineblue 1     " 

Antimony 4     " 

Tartar  Emetic 1     " 

Arsenous  oxide  (white  arsenic)..  2    *' 

Barium  chloride 2 

"       nitrate 4 

hydrate 4 

Bismuth 2 

Borax 4 

xCarbon  bisulphide 2 

Citric  Acid 2 

Cobalt  Chloride 1 

Copper  Sulphate  ...     7 

Ether  (common) 5 

Fluor  Spar  7 

Gold  Leaf \  sheet 

Gum  shellac 5  grins. 

Hydrochloric  acid 100 

Indigo  1 

Iodine 1 

Copperas  (iron  sulphate) 4 

Ferrous  sulphide 7 

Lead  acetate 10 

Lead  oxide  (litharge) 5    " 

Litmus  paper  (red  and  blue( . .   .  1  «q.  icm. 


Magnesium  sulphate., 
ribbon .... 

Manganese  dioxide. . . . 
Mercuric  chloride. ..  . 
*Mercuric  cyanide .... 

Mercury ....    

Nickel 

Nitric  Acid 

Tannic  acid 

xOliveoil 8 

Oxalic  acid 2 

TPiei  ic  acid 1 

Phosphorus 

Potassium  (under  naptha).    . . 

Potassium  bichromate 

Potassium  carbonate  

Potassium  chlorate 

Potassium  ferrocyariide 

Potassium  ludrate 

Potassium  iodide 

Potassium  permanganate 

Silver  nitrate 

Sodium  (under  naptha) 5 

Strontium  (nitrate) 2 

Sulphur  (brimstone) 10 

Sulphuric  acid 200 

Tin   2 

Tin  chloride 5 

*Tartaric  acid 2 

*Turj>entine .     3 

Zinc  (drop) 25 


5  grms. 

1  dcm. 

100  grms. 

'.".'.'.'.'.     5kgm. 

1  grm. 

100    " 


1-20  «tick 
.5  grins. 

5  " 
10  " 
80  " 

5     " 

5     " 

2 

1 

5 


APPARATUS. 


2  Flasks.     (*1  Flask). 
1  Alcohol  Lamp. 

1  Evaporating  Dish. 

*2  Beakers. 

6  Test  Tubes  (*3) 

*1  Mortar  and  Pestle. 

1  Blow  Pipe. 

1  metre  Glass  Tubing. 

3  dcm.  Rubber  Tubing. 

The  above  set  of  Chemicals  and  Apparatus  will  be  forwarded  by  ex- 
press on  receipt  of  price,  expressage  paid  by  purchaser,  or  will  be  for- 
warded C.  0.  D.  on  receipt  of  five  dollars  ($5.00.) 

NoTE.-Marble, 
hydrofluoric  acid 
stand),  Plates,  So 
can  be  obtained  -with  little  difficulty. 


1  Iron  Wire  Gauze,  (\  sq.  dcm..) 

1  Three-cornered  File. 

1  Round  File. 

1  Platinum  Wire,  (1  dcm). 

3  Rubber  Corks. 

*1  Pair  Scales  (metric  weights). 

1  Measuring  Glass  (metric;.  ' 

3  dcm.  Copper  Wire. 

3  sheets  Filtering  Paper. 


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SULPHURIC  ACID,  POTASSIUM  CHLORATE, 

MANGANESE  DIODIDE,  ZINC  (drop), 

And  other  Chemicals  used  in  the  Laboratory. 

THIS  CHEMICAL  PRIMER  may  be  obtained  of 

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lit 
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